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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 155
Endorsed by
University of Cambridge
International Examinations
Cambridge IGCSE
MathematicsCore and Extended
Coursebook
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 255
Karen Morrison and Nick Hamshaw
Cambridge IGCSE
Mathematics Core
and ExtendedCoursebook
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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983139 983137 983149 983138 983154 983145 983140 983143 983141 983157 983150 983145 983158 983141 983154 983155 983145 983156 983161 983152 983154 983141 983155 983155Cambridge New York Melbourne Madrid Cape own SingaporeSatildeo Paulo Delhi Dubai
Cambridge University PressTe Edinburgh Building Cambridge CB2 8RU UK
wwwcambridgeorg
Inormation on this title wwwcambridgeorg9781107606272
copy Cambridge University Press 2012
Tis publication is in copyright Subject to statutory exceptionand to the provisions o relevant collective licensing agreementsno reproduction o any part may take place without the writtenpermission o Cambridge University Press
First published 2012
Printed in the United Kingdom at the University Press Cambridge
A catalogue record for this publication is available from the British Library
ISBN-13 978-1-107-60627-2 Paperback with CD-ROM
Cover image Seamus DitmeyerAlamy
Cambridge University Press has no responsibility or the persistence oraccuracy o URLs or external or third-party Internet websites reerred to inthis publication and does not guarantee that any content on such websites isor will remain accurate or appropriate Inormation regarding prices traveltimetables and other actual inormation given in this work are correct atthe time o 1047297rst printing but Cambridge University Press does not guaranteethe accuracy o such inormation thereafer
983150983151983156983145983139983141 983156983151 983156983141983137983139983144983141983154983155Reerences to Activities contained in these resources are provided lsquoas isrsquo andinormation provided is on the understanding that teachers and techniciansshall undertake a thorough and appropriate risk assessment beoreundertaking any o the Activities listed Cambridge University Press makesno warranties representations or claims o any kind concerning the Activitieso the extent permitted by law Cambridge University Press will not be liableor any loss injury claim liability or damage o any kind resulting rom theuse o the Activities
IGCSEreg is the registered trademark o University o Cambridge International Examinations
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 455Contents
ContentsIntroduction
Acknowledgements
Unit 1
Chapter 3 Lines angles and shapes31 Lines and angles 32 Triangles 33 Quadrilaterals 34 Polygons 35 Circles 36 Construction
Chapter 4 Collecting organising anddisplaying data41 Collecting and classifying data 42 Organising data 43 Using charts to display data
Unit 2
Unit 3
Chapter 7 Perimeter area and volume71 Perimeter and area in two-dimensions 72 Three-dimensional objects 73 Surface areas and volumes of solids
Chapter 8 Introduction to probability81 Basic probability 82 Theoretical probability
83 The probability that an event does nothappen 84 Possibility diagrams 85 Combining independent and mutually
exclusive events
113 Understanding similar shapes
114 Understanding congruence
Chapter 12 Averages and measures of spread
121 Different types of average
122 Making comparisons using averages
and ranges
123 Calculating averages and ranges forfrequency data
124 Calculating averages and ranges for grouped
continuous data
125 Percentiles and quartiles
Chapter 1 Reviewing number concepts11 Different types of numbers 212 Multiples and factors 313 Prime numbers 614 Powers and roots 1015 Working with directed numbers 1316 Order of operations 1417 Rounding numbers 18
Chapter 2 Making sense of algebra21 Using letters to represent
unknown values 2322 Substitution 25
23 Simplifying expressions 2724 Working with brackets 3125 Indices 33
Chapter 5 Fractions51 Equivalent fractions 9952 Operations on fractions 10053 Percentages 10554 Standard form 11055 Your calculator and standard form 11456 Estimation 115
Chapter 6 Equations and transforming formulae
61 Further expansions of brackets 11962 Solving linear equations 12163 Factorising algebraic expressions 12364 Transformation of a formula 124
Chapter 9 Sequences and sets91 Sequences 16592 Rational and irrational numbers 17093 Sets 172
Chapter 10 Straight lines and quadratic equations
101 Straight lines 184
102 Quadratic expressions 198Chapter 11 Pythagorasrsquo theorem andsimilar shapes
111 Pythagorasrsquo theorem 207
112 Understanding similar triangles 211
Examination practice structured question for Unit 1-3
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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Contentsiv
Chapter 13 Understanding measurement
131 Understanding units 251
132 Time 253
133 Upper and lower bounds 257
134 Conversion graphs 262
135 More money 264
Chapter 14 Further solving of equations andinequalities
141 Simultaneous linear equations 268
142 Linear inequalities 275
143 Regions in a plane 279
144 Linear programming 284
145 Completing the square 286
146 Quadratic formula 287
147 Factorising quadratics where the coefficient
of lsquo x 2lsquos is not 1 289
148 Algebraic fractions 291
Chapter 15 Scale drawings bearings andtrigonometry
151 Scale Drawings 3
152 Bearings 3
153 Understanding the tangent cosine
and sine ratios 3
154 Solving problems usingtrigonometry 3
155 Angles between 90deg and 180deg 3
156 The sine and cosine rules 3
157 Area of a triangle 3
158 Trigonometry in three-dimensions 3
Chapter 16 Scatter diagramsand correlation161 Introduction to bivariate data 3
Unit 4
Unit 5
Chapter 17 Managing money
171 Earning money 352
172 Borrowing and investing money 357
173 Buying and selling 363
Chapter 18 Curved graphs
181 Plotting quadratic graphs (the parabola) 371
182 Plotting reciprocal graphs (the hyperbola) 375
183 Using graphs to solve quadratic equations 377
184 Using graphs to solve simultaneous linear
and non-linear equations 379
185 Other non-linear graphs 381
186 Finding the gradient of a curve 390
Chapter 19 Symmetry and loci191 Symmetry in two-dimensions 3192 Symmetry in three-dimensions 4193 Symmetry properties of circles 4194 Angle relationships in circles 4195 Locus 4
Chapter 20 Histograms and frequency distributiondiagrams
201 Histograms 4
202 Cumulative frequency 4
Unit 6
Chapter 21 Ratio rate and proportion
211 Working with ratio 442
212 Ratio and scale 446
213 Rates 450
214 Kinematic graphs 452
215 Proportion 460
216 Direct and inverse proportion in
algebraic terms 463
217 Increasing and decreasing amounts
by a given ratio 467
Chapter 22 More equations formulae andfunctions
221 Setting up equations to solve problems 472
222 Using and transforming formulae 474
223 Functions and function notation 477
Chapter 23 Transformations and matrices
231 Simple plane transformations 4
232 Vectors 5
233 Further transformations 5
234 Matrices and matrix transformation 5
235 Matrices and transformations 5
Chapter 24 Probability using tree diagrams
241 Using tree diagrams to show outcomes 5
242 Calculating probability from tree diagrams 5
Examination practice structured question for Unit 4-6 5
Exercise Answers 5
Glossary 6
Index 6
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 655Introduction
IntroductionTis highly illustrated coursebook covers the complete Cambridge IGCSE Mathematics (0580syllabus Core and Extended material is combined in one book offering a one-stop-shop or
all students and teachers Useul hints are included in the margins or students needing moresupport leaving the narrative clear and to the point Te material required or the Extendedcourse is clearly marked using colour panels and these students are given access to the parts othe Core syllabus they need without having to use an additional book
Te coursebook has been written with a clear progression rom start to 1047297nish with some laterchapters requiring knowledge learnt in earlier chapters Tere are useul signposts throughouthe coursebook that link the content o the chapters allowing the individual to ollow their owcourse through the book where the content in one chapter might require knowledge rom aprevious chapter a comment is included in a lsquoRewindrsquo box and where content will be coveredmore detail later on in the coursebook a comment is included in a lsquoFast orwardrsquo box Exampo both are included here
Worked examples are used throughout to demonstrate each method using typical workings a
thought processes Tese present the methods to the students in a practical and easy-to-ollowway that minimises the need or lengthy explanations
Tere is plenty o practice offered via lsquodrillrsquo exercises throughout each chapter Te exercisesare progressive questions which allow the student to practise methods that have just beenintroduced At the end o each chapter there are lsquoExam-stylersquo questions and lsquoPast paperrsquoquestions Te exam-style questions have been written by the authors in the style o questionson exam papers Te past paper questions are real questions taken rom past exam papers Tend o chapter questions typically re1047298ect the lsquoshortrsquo Paper 1 (Core) and Paper 2 (Extended)questions though you will 1047297nd some more structured ones in there as well Te answers to alo these questions are supplied at the back o the book allowing sel- andor class- assessmenStudents can assess their progress as they go along choosing to do more or less practise asrequired
Te lsquosuggestedrsquo progression through the coursebook is or Units 1-3 to be covered in the1047297rst year o both courses and Units 4-6 to be covered in the second year o both coursesOn this basis there is mixed exam practice at the end o Unit 3 and the end o Unit 6 Tis ishowever only a suggested structure and the course can be taught in various different waysthe signposting throughout the coursebook means that it can be used alongside any order oteaching Te end o Unit questions represent the longer answer lsquostructuredrsquo questions o Pap(Core) and Paper 4 (Extended) exam papers and will use a combination o methods rom acrall relevant chapters As with the end o chapter questions these are a mixture o lsquoExam-stylersquoand lsquoPast paperrsquo questions Te answers to these questions are on the eacherrsquos resource so thathey can be used in classroom tests or or homework i desired
Te coursebook also comes with a glossary to provide a de1047297nition or important tricky term
Helpul guides in the margin o the book include
Hints these are general comments to remind you o important or key inormation that is use
to tackle an exercise or simply useul to know Tey ofen provide extra inormation or suppoin potentially tricky topics
You learned how to plot lines from
equations in chapter 10
REWIND
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or otheritems that are often placed inside
curly brackets
FAST FORWARD
Remember lsquocoefficientrsquo is the number in the term
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 755Introduction vi
ip these are tips that relate to the exam Tey cover common pitalls based on the authorsrsquo experiences o their students and give you things to be wary o or to remember in order toscore marks in the exam Please note that this advice is not rom the University of CambridgeInternational Examinations Syndicate and they bear no responsibility or any such advice given
Te accompanying student CD-ROM at the back o the coursebook includes
A lsquocoverage gridrsquo to map the contents o the syllabus to the topics and chapters in thebullcoursebook
A lsquoCalculator supportrsquo chapter Tis chapter covers the main uses o calculators thatbullstudents seem to struggle with and includes some worksheets to provide practice at usingyour calculator in these situations
RevisionbullCore revision worksheets (and answers) provide extra exercises or each chapter o thebullbook Tese worksheets contain only content rom the Core syllabus
Extended revision worksheets (and answers) provide extra exercises or each chapterbullo the book Tese worksheets contain the same questions as the Core worksheets inaddition to some more challenging questions and questions to cover content unique
to the Extended syllabus Students are encouraged to do some (i not all) o the lsquoCorersquoquestions on these worksheets as well as the Extended ones (shaded) in order to ullyrevise the course I time is limited you might 1047297nd it easier to pick two or three lsquoCorersquoquestions to do beore moving on to the lsquoExtendedrsquo questions
Quick revision tests ndash these are interactive questions in the orm o multiple choice drbulland drop or hide and reveal Tey are quick-1047297re questions to test yoursel in a differenmedium to pen and paper and to get you thinking on the spot Tey cover the Corecontent with only a ew additional screens being speci1047297c to the Extended course Teris at least one activity or each chapter Students are recommended to use the Revisioworksheets for a more comprehensive revision exercise
Worked solutions ndash these are interactive hide and reveal screens showing workedbullsolutions to some o the end o chapter examination practice questions Some o thesewill be lsquoExam-stylersquo and some will be lsquoPast paperrsquo questions but all will be taken romthe end o the chapter Tere will be at least one or each chapter Te screen includesthe question and the answer but also includes a series o lsquoCluersquo or lsquoiprsquo boxes Te lsquoCluboxes can be clicked on to reveal a clue to help the student i they are struggling withhow to approach the question Te lsquoiprsquo boxes contain tips relating to the exam just likthe lsquoiprsquo boxes in the coursebook
Also in the Cambridge IGCSE Mathematics series are two Practice Books ndash one or Core and onor Extended ndash to offer students targeted practice Tese ollow the chapters and topics o thecoursebook including additional exercises or those who want more practice Tese too includlsquoHintsrsquo and lsquoipsrsquo to help with tricky topics
It is essential that youremember to work outboth unknowns Every
pair o simultaneous linearequations will have a pairo solutions
Tip
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 855Acknowledgements
AcknowledgementsTe authors and publishers acknowledge the following sources of copyright material and are grateful for the permissionsgranted
Past paper examination questions are reproduced by permission o University o Cambridge International Examinations
Cover image Seamus DitmeyerAlamy p 1 copy sanderderwildecom p 13 Dmitry LavruhinShutterstock p 13 HadriannShutterstop 13 Jason CoxShutterstock p 13 Ruslan NabiyevShutterstock p 46 IvangottShutterstock p 47 Claudio Baldini Shutterstock pakiyokoShutterstock p 73 INSAGOShutterstock p 98 copy Te rustees o the British Museum p 119 Wikipedia p 128 FrancescoDazziShutterstock p 164 North Wind Picture ArchiveAlamy p 148 Paolo GiantiShutterstock pp 153 341 487 533 iStockphotTinkstock p 155 Opachevsky IrinaShutterstock p 156 Chad LittlejohnShutterstock p 159 sahua dShutterstock p 206 PhotoscomTinkstock pp 223 419 428 Mike van der Wold p 235 Pics1047297veShutterstock p 250 Vladislav Gur1047297nkelShutterstock p 259Mike an CShutterstock p 261 SuzanShutterstock p 261 R-studioShutterstock p 264 Galyna AndrushkoShutterstock p 29Gustavo Miguel FernandesShutterstock p 351 Stephanie FrayShutterstock p 375 Kristina PostnikovaShutterstock p 397 ConnBrosShutterstock p 441 Philippe WojazerAPPress Association Images
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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Karen Morrison and Nick Hamshaw
Cambridge IGCSE
Mathematics Core
and ExtendedCoursebook
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983139 983137 983149 983138 983154 983145 983140 983143 983141 983157 983150 983145 983158 983141 983154 983155 983145 983156 983161 983152 983154 983141 983155 983155Cambridge New York Melbourne Madrid Cape own SingaporeSatildeo Paulo Delhi Dubai
Cambridge University PressTe Edinburgh Building Cambridge CB2 8RU UK
wwwcambridgeorg
Inormation on this title wwwcambridgeorg9781107606272
copy Cambridge University Press 2012
Tis publication is in copyright Subject to statutory exceptionand to the provisions o relevant collective licensing agreementsno reproduction o any part may take place without the writtenpermission o Cambridge University Press
First published 2012
Printed in the United Kingdom at the University Press Cambridge
A catalogue record for this publication is available from the British Library
ISBN-13 978-1-107-60627-2 Paperback with CD-ROM
Cover image Seamus DitmeyerAlamy
Cambridge University Press has no responsibility or the persistence oraccuracy o URLs or external or third-party Internet websites reerred to inthis publication and does not guarantee that any content on such websites isor will remain accurate or appropriate Inormation regarding prices traveltimetables and other actual inormation given in this work are correct atthe time o 1047297rst printing but Cambridge University Press does not guaranteethe accuracy o such inormation thereafer
983150983151983156983145983139983141 983156983151 983156983141983137983139983144983141983154983155Reerences to Activities contained in these resources are provided lsquoas isrsquo andinormation provided is on the understanding that teachers and techniciansshall undertake a thorough and appropriate risk assessment beoreundertaking any o the Activities listed Cambridge University Press makesno warranties representations or claims o any kind concerning the Activitieso the extent permitted by law Cambridge University Press will not be liableor any loss injury claim liability or damage o any kind resulting rom theuse o the Activities
IGCSEreg is the registered trademark o University o Cambridge International Examinations
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 455Contents
ContentsIntroduction
Acknowledgements
Unit 1
Chapter 3 Lines angles and shapes31 Lines and angles 32 Triangles 33 Quadrilaterals 34 Polygons 35 Circles 36 Construction
Chapter 4 Collecting organising anddisplaying data41 Collecting and classifying data 42 Organising data 43 Using charts to display data
Unit 2
Unit 3
Chapter 7 Perimeter area and volume71 Perimeter and area in two-dimensions 72 Three-dimensional objects 73 Surface areas and volumes of solids
Chapter 8 Introduction to probability81 Basic probability 82 Theoretical probability
83 The probability that an event does nothappen 84 Possibility diagrams 85 Combining independent and mutually
exclusive events
113 Understanding similar shapes
114 Understanding congruence
Chapter 12 Averages and measures of spread
121 Different types of average
122 Making comparisons using averages
and ranges
123 Calculating averages and ranges forfrequency data
124 Calculating averages and ranges for grouped
continuous data
125 Percentiles and quartiles
Chapter 1 Reviewing number concepts11 Different types of numbers 212 Multiples and factors 313 Prime numbers 614 Powers and roots 1015 Working with directed numbers 1316 Order of operations 1417 Rounding numbers 18
Chapter 2 Making sense of algebra21 Using letters to represent
unknown values 2322 Substitution 25
23 Simplifying expressions 2724 Working with brackets 3125 Indices 33
Chapter 5 Fractions51 Equivalent fractions 9952 Operations on fractions 10053 Percentages 10554 Standard form 11055 Your calculator and standard form 11456 Estimation 115
Chapter 6 Equations and transforming formulae
61 Further expansions of brackets 11962 Solving linear equations 12163 Factorising algebraic expressions 12364 Transformation of a formula 124
Chapter 9 Sequences and sets91 Sequences 16592 Rational and irrational numbers 17093 Sets 172
Chapter 10 Straight lines and quadratic equations
101 Straight lines 184
102 Quadratic expressions 198Chapter 11 Pythagorasrsquo theorem andsimilar shapes
111 Pythagorasrsquo theorem 207
112 Understanding similar triangles 211
Examination practice structured question for Unit 1-3
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Contentsiv
Chapter 13 Understanding measurement
131 Understanding units 251
132 Time 253
133 Upper and lower bounds 257
134 Conversion graphs 262
135 More money 264
Chapter 14 Further solving of equations andinequalities
141 Simultaneous linear equations 268
142 Linear inequalities 275
143 Regions in a plane 279
144 Linear programming 284
145 Completing the square 286
146 Quadratic formula 287
147 Factorising quadratics where the coefficient
of lsquo x 2lsquos is not 1 289
148 Algebraic fractions 291
Chapter 15 Scale drawings bearings andtrigonometry
151 Scale Drawings 3
152 Bearings 3
153 Understanding the tangent cosine
and sine ratios 3
154 Solving problems usingtrigonometry 3
155 Angles between 90deg and 180deg 3
156 The sine and cosine rules 3
157 Area of a triangle 3
158 Trigonometry in three-dimensions 3
Chapter 16 Scatter diagramsand correlation161 Introduction to bivariate data 3
Unit 4
Unit 5
Chapter 17 Managing money
171 Earning money 352
172 Borrowing and investing money 357
173 Buying and selling 363
Chapter 18 Curved graphs
181 Plotting quadratic graphs (the parabola) 371
182 Plotting reciprocal graphs (the hyperbola) 375
183 Using graphs to solve quadratic equations 377
184 Using graphs to solve simultaneous linear
and non-linear equations 379
185 Other non-linear graphs 381
186 Finding the gradient of a curve 390
Chapter 19 Symmetry and loci191 Symmetry in two-dimensions 3192 Symmetry in three-dimensions 4193 Symmetry properties of circles 4194 Angle relationships in circles 4195 Locus 4
Chapter 20 Histograms and frequency distributiondiagrams
201 Histograms 4
202 Cumulative frequency 4
Unit 6
Chapter 21 Ratio rate and proportion
211 Working with ratio 442
212 Ratio and scale 446
213 Rates 450
214 Kinematic graphs 452
215 Proportion 460
216 Direct and inverse proportion in
algebraic terms 463
217 Increasing and decreasing amounts
by a given ratio 467
Chapter 22 More equations formulae andfunctions
221 Setting up equations to solve problems 472
222 Using and transforming formulae 474
223 Functions and function notation 477
Chapter 23 Transformations and matrices
231 Simple plane transformations 4
232 Vectors 5
233 Further transformations 5
234 Matrices and matrix transformation 5
235 Matrices and transformations 5
Chapter 24 Probability using tree diagrams
241 Using tree diagrams to show outcomes 5
242 Calculating probability from tree diagrams 5
Examination practice structured question for Unit 4-6 5
Exercise Answers 5
Glossary 6
Index 6
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 655Introduction
IntroductionTis highly illustrated coursebook covers the complete Cambridge IGCSE Mathematics (0580syllabus Core and Extended material is combined in one book offering a one-stop-shop or
all students and teachers Useul hints are included in the margins or students needing moresupport leaving the narrative clear and to the point Te material required or the Extendedcourse is clearly marked using colour panels and these students are given access to the parts othe Core syllabus they need without having to use an additional book
Te coursebook has been written with a clear progression rom start to 1047297nish with some laterchapters requiring knowledge learnt in earlier chapters Tere are useul signposts throughouthe coursebook that link the content o the chapters allowing the individual to ollow their owcourse through the book where the content in one chapter might require knowledge rom aprevious chapter a comment is included in a lsquoRewindrsquo box and where content will be coveredmore detail later on in the coursebook a comment is included in a lsquoFast orwardrsquo box Exampo both are included here
Worked examples are used throughout to demonstrate each method using typical workings a
thought processes Tese present the methods to the students in a practical and easy-to-ollowway that minimises the need or lengthy explanations
Tere is plenty o practice offered via lsquodrillrsquo exercises throughout each chapter Te exercisesare progressive questions which allow the student to practise methods that have just beenintroduced At the end o each chapter there are lsquoExam-stylersquo questions and lsquoPast paperrsquoquestions Te exam-style questions have been written by the authors in the style o questionson exam papers Te past paper questions are real questions taken rom past exam papers Tend o chapter questions typically re1047298ect the lsquoshortrsquo Paper 1 (Core) and Paper 2 (Extended)questions though you will 1047297nd some more structured ones in there as well Te answers to alo these questions are supplied at the back o the book allowing sel- andor class- assessmenStudents can assess their progress as they go along choosing to do more or less practise asrequired
Te lsquosuggestedrsquo progression through the coursebook is or Units 1-3 to be covered in the1047297rst year o both courses and Units 4-6 to be covered in the second year o both coursesOn this basis there is mixed exam practice at the end o Unit 3 and the end o Unit 6 Tis ishowever only a suggested structure and the course can be taught in various different waysthe signposting throughout the coursebook means that it can be used alongside any order oteaching Te end o Unit questions represent the longer answer lsquostructuredrsquo questions o Pap(Core) and Paper 4 (Extended) exam papers and will use a combination o methods rom acrall relevant chapters As with the end o chapter questions these are a mixture o lsquoExam-stylersquoand lsquoPast paperrsquo questions Te answers to these questions are on the eacherrsquos resource so thathey can be used in classroom tests or or homework i desired
Te coursebook also comes with a glossary to provide a de1047297nition or important tricky term
Helpul guides in the margin o the book include
Hints these are general comments to remind you o important or key inormation that is use
to tackle an exercise or simply useul to know Tey ofen provide extra inormation or suppoin potentially tricky topics
You learned how to plot lines from
equations in chapter 10
REWIND
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or otheritems that are often placed inside
curly brackets
FAST FORWARD
Remember lsquocoefficientrsquo is the number in the term
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 755Introduction vi
ip these are tips that relate to the exam Tey cover common pitalls based on the authorsrsquo experiences o their students and give you things to be wary o or to remember in order toscore marks in the exam Please note that this advice is not rom the University of CambridgeInternational Examinations Syndicate and they bear no responsibility or any such advice given
Te accompanying student CD-ROM at the back o the coursebook includes
A lsquocoverage gridrsquo to map the contents o the syllabus to the topics and chapters in thebullcoursebook
A lsquoCalculator supportrsquo chapter Tis chapter covers the main uses o calculators thatbullstudents seem to struggle with and includes some worksheets to provide practice at usingyour calculator in these situations
RevisionbullCore revision worksheets (and answers) provide extra exercises or each chapter o thebullbook Tese worksheets contain only content rom the Core syllabus
Extended revision worksheets (and answers) provide extra exercises or each chapterbullo the book Tese worksheets contain the same questions as the Core worksheets inaddition to some more challenging questions and questions to cover content unique
to the Extended syllabus Students are encouraged to do some (i not all) o the lsquoCorersquoquestions on these worksheets as well as the Extended ones (shaded) in order to ullyrevise the course I time is limited you might 1047297nd it easier to pick two or three lsquoCorersquoquestions to do beore moving on to the lsquoExtendedrsquo questions
Quick revision tests ndash these are interactive questions in the orm o multiple choice drbulland drop or hide and reveal Tey are quick-1047297re questions to test yoursel in a differenmedium to pen and paper and to get you thinking on the spot Tey cover the Corecontent with only a ew additional screens being speci1047297c to the Extended course Teris at least one activity or each chapter Students are recommended to use the Revisioworksheets for a more comprehensive revision exercise
Worked solutions ndash these are interactive hide and reveal screens showing workedbullsolutions to some o the end o chapter examination practice questions Some o thesewill be lsquoExam-stylersquo and some will be lsquoPast paperrsquo questions but all will be taken romthe end o the chapter Tere will be at least one or each chapter Te screen includesthe question and the answer but also includes a series o lsquoCluersquo or lsquoiprsquo boxes Te lsquoCluboxes can be clicked on to reveal a clue to help the student i they are struggling withhow to approach the question Te lsquoiprsquo boxes contain tips relating to the exam just likthe lsquoiprsquo boxes in the coursebook
Also in the Cambridge IGCSE Mathematics series are two Practice Books ndash one or Core and onor Extended ndash to offer students targeted practice Tese ollow the chapters and topics o thecoursebook including additional exercises or those who want more practice Tese too includlsquoHintsrsquo and lsquoipsrsquo to help with tricky topics
It is essential that youremember to work outboth unknowns Every
pair o simultaneous linearequations will have a pairo solutions
Tip
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 855Acknowledgements
AcknowledgementsTe authors and publishers acknowledge the following sources of copyright material and are grateful for the permissionsgranted
Past paper examination questions are reproduced by permission o University o Cambridge International Examinations
Cover image Seamus DitmeyerAlamy p 1 copy sanderderwildecom p 13 Dmitry LavruhinShutterstock p 13 HadriannShutterstop 13 Jason CoxShutterstock p 13 Ruslan NabiyevShutterstock p 46 IvangottShutterstock p 47 Claudio Baldini Shutterstock pakiyokoShutterstock p 73 INSAGOShutterstock p 98 copy Te rustees o the British Museum p 119 Wikipedia p 128 FrancescoDazziShutterstock p 164 North Wind Picture ArchiveAlamy p 148 Paolo GiantiShutterstock pp 153 341 487 533 iStockphotTinkstock p 155 Opachevsky IrinaShutterstock p 156 Chad LittlejohnShutterstock p 159 sahua dShutterstock p 206 PhotoscomTinkstock pp 223 419 428 Mike van der Wold p 235 Pics1047297veShutterstock p 250 Vladislav Gur1047297nkelShutterstock p 259Mike an CShutterstock p 261 SuzanShutterstock p 261 R-studioShutterstock p 264 Galyna AndrushkoShutterstock p 29Gustavo Miguel FernandesShutterstock p 351 Stephanie FrayShutterstock p 375 Kristina PostnikovaShutterstock p 397 ConnBrosShutterstock p 441 Philippe WojazerAPPress Association Images
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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983139 983137 983149 983138 983154 983145 983140 983143 983141 983157 983150 983145 983158 983141 983154 983155 983145 983156 983161 983152 983154 983141 983155 983155Cambridge New York Melbourne Madrid Cape own SingaporeSatildeo Paulo Delhi Dubai
Cambridge University PressTe Edinburgh Building Cambridge CB2 8RU UK
wwwcambridgeorg
Inormation on this title wwwcambridgeorg9781107606272
copy Cambridge University Press 2012
Tis publication is in copyright Subject to statutory exceptionand to the provisions o relevant collective licensing agreementsno reproduction o any part may take place without the writtenpermission o Cambridge University Press
First published 2012
Printed in the United Kingdom at the University Press Cambridge
A catalogue record for this publication is available from the British Library
ISBN-13 978-1-107-60627-2 Paperback with CD-ROM
Cover image Seamus DitmeyerAlamy
Cambridge University Press has no responsibility or the persistence oraccuracy o URLs or external or third-party Internet websites reerred to inthis publication and does not guarantee that any content on such websites isor will remain accurate or appropriate Inormation regarding prices traveltimetables and other actual inormation given in this work are correct atthe time o 1047297rst printing but Cambridge University Press does not guaranteethe accuracy o such inormation thereafer
983150983151983156983145983139983141 983156983151 983156983141983137983139983144983141983154983155Reerences to Activities contained in these resources are provided lsquoas isrsquo andinormation provided is on the understanding that teachers and techniciansshall undertake a thorough and appropriate risk assessment beoreundertaking any o the Activities listed Cambridge University Press makesno warranties representations or claims o any kind concerning the Activitieso the extent permitted by law Cambridge University Press will not be liableor any loss injury claim liability or damage o any kind resulting rom theuse o the Activities
IGCSEreg is the registered trademark o University o Cambridge International Examinations
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 455Contents
ContentsIntroduction
Acknowledgements
Unit 1
Chapter 3 Lines angles and shapes31 Lines and angles 32 Triangles 33 Quadrilaterals 34 Polygons 35 Circles 36 Construction
Chapter 4 Collecting organising anddisplaying data41 Collecting and classifying data 42 Organising data 43 Using charts to display data
Unit 2
Unit 3
Chapter 7 Perimeter area and volume71 Perimeter and area in two-dimensions 72 Three-dimensional objects 73 Surface areas and volumes of solids
Chapter 8 Introduction to probability81 Basic probability 82 Theoretical probability
83 The probability that an event does nothappen 84 Possibility diagrams 85 Combining independent and mutually
exclusive events
113 Understanding similar shapes
114 Understanding congruence
Chapter 12 Averages and measures of spread
121 Different types of average
122 Making comparisons using averages
and ranges
123 Calculating averages and ranges forfrequency data
124 Calculating averages and ranges for grouped
continuous data
125 Percentiles and quartiles
Chapter 1 Reviewing number concepts11 Different types of numbers 212 Multiples and factors 313 Prime numbers 614 Powers and roots 1015 Working with directed numbers 1316 Order of operations 1417 Rounding numbers 18
Chapter 2 Making sense of algebra21 Using letters to represent
unknown values 2322 Substitution 25
23 Simplifying expressions 2724 Working with brackets 3125 Indices 33
Chapter 5 Fractions51 Equivalent fractions 9952 Operations on fractions 10053 Percentages 10554 Standard form 11055 Your calculator and standard form 11456 Estimation 115
Chapter 6 Equations and transforming formulae
61 Further expansions of brackets 11962 Solving linear equations 12163 Factorising algebraic expressions 12364 Transformation of a formula 124
Chapter 9 Sequences and sets91 Sequences 16592 Rational and irrational numbers 17093 Sets 172
Chapter 10 Straight lines and quadratic equations
101 Straight lines 184
102 Quadratic expressions 198Chapter 11 Pythagorasrsquo theorem andsimilar shapes
111 Pythagorasrsquo theorem 207
112 Understanding similar triangles 211
Examination practice structured question for Unit 1-3
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Contentsiv
Chapter 13 Understanding measurement
131 Understanding units 251
132 Time 253
133 Upper and lower bounds 257
134 Conversion graphs 262
135 More money 264
Chapter 14 Further solving of equations andinequalities
141 Simultaneous linear equations 268
142 Linear inequalities 275
143 Regions in a plane 279
144 Linear programming 284
145 Completing the square 286
146 Quadratic formula 287
147 Factorising quadratics where the coefficient
of lsquo x 2lsquos is not 1 289
148 Algebraic fractions 291
Chapter 15 Scale drawings bearings andtrigonometry
151 Scale Drawings 3
152 Bearings 3
153 Understanding the tangent cosine
and sine ratios 3
154 Solving problems usingtrigonometry 3
155 Angles between 90deg and 180deg 3
156 The sine and cosine rules 3
157 Area of a triangle 3
158 Trigonometry in three-dimensions 3
Chapter 16 Scatter diagramsand correlation161 Introduction to bivariate data 3
Unit 4
Unit 5
Chapter 17 Managing money
171 Earning money 352
172 Borrowing and investing money 357
173 Buying and selling 363
Chapter 18 Curved graphs
181 Plotting quadratic graphs (the parabola) 371
182 Plotting reciprocal graphs (the hyperbola) 375
183 Using graphs to solve quadratic equations 377
184 Using graphs to solve simultaneous linear
and non-linear equations 379
185 Other non-linear graphs 381
186 Finding the gradient of a curve 390
Chapter 19 Symmetry and loci191 Symmetry in two-dimensions 3192 Symmetry in three-dimensions 4193 Symmetry properties of circles 4194 Angle relationships in circles 4195 Locus 4
Chapter 20 Histograms and frequency distributiondiagrams
201 Histograms 4
202 Cumulative frequency 4
Unit 6
Chapter 21 Ratio rate and proportion
211 Working with ratio 442
212 Ratio and scale 446
213 Rates 450
214 Kinematic graphs 452
215 Proportion 460
216 Direct and inverse proportion in
algebraic terms 463
217 Increasing and decreasing amounts
by a given ratio 467
Chapter 22 More equations formulae andfunctions
221 Setting up equations to solve problems 472
222 Using and transforming formulae 474
223 Functions and function notation 477
Chapter 23 Transformations and matrices
231 Simple plane transformations 4
232 Vectors 5
233 Further transformations 5
234 Matrices and matrix transformation 5
235 Matrices and transformations 5
Chapter 24 Probability using tree diagrams
241 Using tree diagrams to show outcomes 5
242 Calculating probability from tree diagrams 5
Examination practice structured question for Unit 4-6 5
Exercise Answers 5
Glossary 6
Index 6
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 655Introduction
IntroductionTis highly illustrated coursebook covers the complete Cambridge IGCSE Mathematics (0580syllabus Core and Extended material is combined in one book offering a one-stop-shop or
all students and teachers Useul hints are included in the margins or students needing moresupport leaving the narrative clear and to the point Te material required or the Extendedcourse is clearly marked using colour panels and these students are given access to the parts othe Core syllabus they need without having to use an additional book
Te coursebook has been written with a clear progression rom start to 1047297nish with some laterchapters requiring knowledge learnt in earlier chapters Tere are useul signposts throughouthe coursebook that link the content o the chapters allowing the individual to ollow their owcourse through the book where the content in one chapter might require knowledge rom aprevious chapter a comment is included in a lsquoRewindrsquo box and where content will be coveredmore detail later on in the coursebook a comment is included in a lsquoFast orwardrsquo box Exampo both are included here
Worked examples are used throughout to demonstrate each method using typical workings a
thought processes Tese present the methods to the students in a practical and easy-to-ollowway that minimises the need or lengthy explanations
Tere is plenty o practice offered via lsquodrillrsquo exercises throughout each chapter Te exercisesare progressive questions which allow the student to practise methods that have just beenintroduced At the end o each chapter there are lsquoExam-stylersquo questions and lsquoPast paperrsquoquestions Te exam-style questions have been written by the authors in the style o questionson exam papers Te past paper questions are real questions taken rom past exam papers Tend o chapter questions typically re1047298ect the lsquoshortrsquo Paper 1 (Core) and Paper 2 (Extended)questions though you will 1047297nd some more structured ones in there as well Te answers to alo these questions are supplied at the back o the book allowing sel- andor class- assessmenStudents can assess their progress as they go along choosing to do more or less practise asrequired
Te lsquosuggestedrsquo progression through the coursebook is or Units 1-3 to be covered in the1047297rst year o both courses and Units 4-6 to be covered in the second year o both coursesOn this basis there is mixed exam practice at the end o Unit 3 and the end o Unit 6 Tis ishowever only a suggested structure and the course can be taught in various different waysthe signposting throughout the coursebook means that it can be used alongside any order oteaching Te end o Unit questions represent the longer answer lsquostructuredrsquo questions o Pap(Core) and Paper 4 (Extended) exam papers and will use a combination o methods rom acrall relevant chapters As with the end o chapter questions these are a mixture o lsquoExam-stylersquoand lsquoPast paperrsquo questions Te answers to these questions are on the eacherrsquos resource so thathey can be used in classroom tests or or homework i desired
Te coursebook also comes with a glossary to provide a de1047297nition or important tricky term
Helpul guides in the margin o the book include
Hints these are general comments to remind you o important or key inormation that is use
to tackle an exercise or simply useul to know Tey ofen provide extra inormation or suppoin potentially tricky topics
You learned how to plot lines from
equations in chapter 10
REWIND
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or otheritems that are often placed inside
curly brackets
FAST FORWARD
Remember lsquocoefficientrsquo is the number in the term
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 755Introduction vi
ip these are tips that relate to the exam Tey cover common pitalls based on the authorsrsquo experiences o their students and give you things to be wary o or to remember in order toscore marks in the exam Please note that this advice is not rom the University of CambridgeInternational Examinations Syndicate and they bear no responsibility or any such advice given
Te accompanying student CD-ROM at the back o the coursebook includes
A lsquocoverage gridrsquo to map the contents o the syllabus to the topics and chapters in thebullcoursebook
A lsquoCalculator supportrsquo chapter Tis chapter covers the main uses o calculators thatbullstudents seem to struggle with and includes some worksheets to provide practice at usingyour calculator in these situations
RevisionbullCore revision worksheets (and answers) provide extra exercises or each chapter o thebullbook Tese worksheets contain only content rom the Core syllabus
Extended revision worksheets (and answers) provide extra exercises or each chapterbullo the book Tese worksheets contain the same questions as the Core worksheets inaddition to some more challenging questions and questions to cover content unique
to the Extended syllabus Students are encouraged to do some (i not all) o the lsquoCorersquoquestions on these worksheets as well as the Extended ones (shaded) in order to ullyrevise the course I time is limited you might 1047297nd it easier to pick two or three lsquoCorersquoquestions to do beore moving on to the lsquoExtendedrsquo questions
Quick revision tests ndash these are interactive questions in the orm o multiple choice drbulland drop or hide and reveal Tey are quick-1047297re questions to test yoursel in a differenmedium to pen and paper and to get you thinking on the spot Tey cover the Corecontent with only a ew additional screens being speci1047297c to the Extended course Teris at least one activity or each chapter Students are recommended to use the Revisioworksheets for a more comprehensive revision exercise
Worked solutions ndash these are interactive hide and reveal screens showing workedbullsolutions to some o the end o chapter examination practice questions Some o thesewill be lsquoExam-stylersquo and some will be lsquoPast paperrsquo questions but all will be taken romthe end o the chapter Tere will be at least one or each chapter Te screen includesthe question and the answer but also includes a series o lsquoCluersquo or lsquoiprsquo boxes Te lsquoCluboxes can be clicked on to reveal a clue to help the student i they are struggling withhow to approach the question Te lsquoiprsquo boxes contain tips relating to the exam just likthe lsquoiprsquo boxes in the coursebook
Also in the Cambridge IGCSE Mathematics series are two Practice Books ndash one or Core and onor Extended ndash to offer students targeted practice Tese ollow the chapters and topics o thecoursebook including additional exercises or those who want more practice Tese too includlsquoHintsrsquo and lsquoipsrsquo to help with tricky topics
It is essential that youremember to work outboth unknowns Every
pair o simultaneous linearequations will have a pairo solutions
Tip
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 855Acknowledgements
AcknowledgementsTe authors and publishers acknowledge the following sources of copyright material and are grateful for the permissionsgranted
Past paper examination questions are reproduced by permission o University o Cambridge International Examinations
Cover image Seamus DitmeyerAlamy p 1 copy sanderderwildecom p 13 Dmitry LavruhinShutterstock p 13 HadriannShutterstop 13 Jason CoxShutterstock p 13 Ruslan NabiyevShutterstock p 46 IvangottShutterstock p 47 Claudio Baldini Shutterstock pakiyokoShutterstock p 73 INSAGOShutterstock p 98 copy Te rustees o the British Museum p 119 Wikipedia p 128 FrancescoDazziShutterstock p 164 North Wind Picture ArchiveAlamy p 148 Paolo GiantiShutterstock pp 153 341 487 533 iStockphotTinkstock p 155 Opachevsky IrinaShutterstock p 156 Chad LittlejohnShutterstock p 159 sahua dShutterstock p 206 PhotoscomTinkstock pp 223 419 428 Mike van der Wold p 235 Pics1047297veShutterstock p 250 Vladislav Gur1047297nkelShutterstock p 259Mike an CShutterstock p 261 SuzanShutterstock p 261 R-studioShutterstock p 264 Galyna AndrushkoShutterstock p 29Gustavo Miguel FernandesShutterstock p 351 Stephanie FrayShutterstock p 375 Kristina PostnikovaShutterstock p 397 ConnBrosShutterstock p 441 Philippe WojazerAPPress Association Images
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 455Contents
ContentsIntroduction
Acknowledgements
Unit 1
Chapter 3 Lines angles and shapes31 Lines and angles 32 Triangles 33 Quadrilaterals 34 Polygons 35 Circles 36 Construction
Chapter 4 Collecting organising anddisplaying data41 Collecting and classifying data 42 Organising data 43 Using charts to display data
Unit 2
Unit 3
Chapter 7 Perimeter area and volume71 Perimeter and area in two-dimensions 72 Three-dimensional objects 73 Surface areas and volumes of solids
Chapter 8 Introduction to probability81 Basic probability 82 Theoretical probability
83 The probability that an event does nothappen 84 Possibility diagrams 85 Combining independent and mutually
exclusive events
113 Understanding similar shapes
114 Understanding congruence
Chapter 12 Averages and measures of spread
121 Different types of average
122 Making comparisons using averages
and ranges
123 Calculating averages and ranges forfrequency data
124 Calculating averages and ranges for grouped
continuous data
125 Percentiles and quartiles
Chapter 1 Reviewing number concepts11 Different types of numbers 212 Multiples and factors 313 Prime numbers 614 Powers and roots 1015 Working with directed numbers 1316 Order of operations 1417 Rounding numbers 18
Chapter 2 Making sense of algebra21 Using letters to represent
unknown values 2322 Substitution 25
23 Simplifying expressions 2724 Working with brackets 3125 Indices 33
Chapter 5 Fractions51 Equivalent fractions 9952 Operations on fractions 10053 Percentages 10554 Standard form 11055 Your calculator and standard form 11456 Estimation 115
Chapter 6 Equations and transforming formulae
61 Further expansions of brackets 11962 Solving linear equations 12163 Factorising algebraic expressions 12364 Transformation of a formula 124
Chapter 9 Sequences and sets91 Sequences 16592 Rational and irrational numbers 17093 Sets 172
Chapter 10 Straight lines and quadratic equations
101 Straight lines 184
102 Quadratic expressions 198Chapter 11 Pythagorasrsquo theorem andsimilar shapes
111 Pythagorasrsquo theorem 207
112 Understanding similar triangles 211
Examination practice structured question for Unit 1-3
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Contentsiv
Chapter 13 Understanding measurement
131 Understanding units 251
132 Time 253
133 Upper and lower bounds 257
134 Conversion graphs 262
135 More money 264
Chapter 14 Further solving of equations andinequalities
141 Simultaneous linear equations 268
142 Linear inequalities 275
143 Regions in a plane 279
144 Linear programming 284
145 Completing the square 286
146 Quadratic formula 287
147 Factorising quadratics where the coefficient
of lsquo x 2lsquos is not 1 289
148 Algebraic fractions 291
Chapter 15 Scale drawings bearings andtrigonometry
151 Scale Drawings 3
152 Bearings 3
153 Understanding the tangent cosine
and sine ratios 3
154 Solving problems usingtrigonometry 3
155 Angles between 90deg and 180deg 3
156 The sine and cosine rules 3
157 Area of a triangle 3
158 Trigonometry in three-dimensions 3
Chapter 16 Scatter diagramsand correlation161 Introduction to bivariate data 3
Unit 4
Unit 5
Chapter 17 Managing money
171 Earning money 352
172 Borrowing and investing money 357
173 Buying and selling 363
Chapter 18 Curved graphs
181 Plotting quadratic graphs (the parabola) 371
182 Plotting reciprocal graphs (the hyperbola) 375
183 Using graphs to solve quadratic equations 377
184 Using graphs to solve simultaneous linear
and non-linear equations 379
185 Other non-linear graphs 381
186 Finding the gradient of a curve 390
Chapter 19 Symmetry and loci191 Symmetry in two-dimensions 3192 Symmetry in three-dimensions 4193 Symmetry properties of circles 4194 Angle relationships in circles 4195 Locus 4
Chapter 20 Histograms and frequency distributiondiagrams
201 Histograms 4
202 Cumulative frequency 4
Unit 6
Chapter 21 Ratio rate and proportion
211 Working with ratio 442
212 Ratio and scale 446
213 Rates 450
214 Kinematic graphs 452
215 Proportion 460
216 Direct and inverse proportion in
algebraic terms 463
217 Increasing and decreasing amounts
by a given ratio 467
Chapter 22 More equations formulae andfunctions
221 Setting up equations to solve problems 472
222 Using and transforming formulae 474
223 Functions and function notation 477
Chapter 23 Transformations and matrices
231 Simple plane transformations 4
232 Vectors 5
233 Further transformations 5
234 Matrices and matrix transformation 5
235 Matrices and transformations 5
Chapter 24 Probability using tree diagrams
241 Using tree diagrams to show outcomes 5
242 Calculating probability from tree diagrams 5
Examination practice structured question for Unit 4-6 5
Exercise Answers 5
Glossary 6
Index 6
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 655Introduction
IntroductionTis highly illustrated coursebook covers the complete Cambridge IGCSE Mathematics (0580syllabus Core and Extended material is combined in one book offering a one-stop-shop or
all students and teachers Useul hints are included in the margins or students needing moresupport leaving the narrative clear and to the point Te material required or the Extendedcourse is clearly marked using colour panels and these students are given access to the parts othe Core syllabus they need without having to use an additional book
Te coursebook has been written with a clear progression rom start to 1047297nish with some laterchapters requiring knowledge learnt in earlier chapters Tere are useul signposts throughouthe coursebook that link the content o the chapters allowing the individual to ollow their owcourse through the book where the content in one chapter might require knowledge rom aprevious chapter a comment is included in a lsquoRewindrsquo box and where content will be coveredmore detail later on in the coursebook a comment is included in a lsquoFast orwardrsquo box Exampo both are included here
Worked examples are used throughout to demonstrate each method using typical workings a
thought processes Tese present the methods to the students in a practical and easy-to-ollowway that minimises the need or lengthy explanations
Tere is plenty o practice offered via lsquodrillrsquo exercises throughout each chapter Te exercisesare progressive questions which allow the student to practise methods that have just beenintroduced At the end o each chapter there are lsquoExam-stylersquo questions and lsquoPast paperrsquoquestions Te exam-style questions have been written by the authors in the style o questionson exam papers Te past paper questions are real questions taken rom past exam papers Tend o chapter questions typically re1047298ect the lsquoshortrsquo Paper 1 (Core) and Paper 2 (Extended)questions though you will 1047297nd some more structured ones in there as well Te answers to alo these questions are supplied at the back o the book allowing sel- andor class- assessmenStudents can assess their progress as they go along choosing to do more or less practise asrequired
Te lsquosuggestedrsquo progression through the coursebook is or Units 1-3 to be covered in the1047297rst year o both courses and Units 4-6 to be covered in the second year o both coursesOn this basis there is mixed exam practice at the end o Unit 3 and the end o Unit 6 Tis ishowever only a suggested structure and the course can be taught in various different waysthe signposting throughout the coursebook means that it can be used alongside any order oteaching Te end o Unit questions represent the longer answer lsquostructuredrsquo questions o Pap(Core) and Paper 4 (Extended) exam papers and will use a combination o methods rom acrall relevant chapters As with the end o chapter questions these are a mixture o lsquoExam-stylersquoand lsquoPast paperrsquo questions Te answers to these questions are on the eacherrsquos resource so thathey can be used in classroom tests or or homework i desired
Te coursebook also comes with a glossary to provide a de1047297nition or important tricky term
Helpul guides in the margin o the book include
Hints these are general comments to remind you o important or key inormation that is use
to tackle an exercise or simply useul to know Tey ofen provide extra inormation or suppoin potentially tricky topics
You learned how to plot lines from
equations in chapter 10
REWIND
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or otheritems that are often placed inside
curly brackets
FAST FORWARD
Remember lsquocoefficientrsquo is the number in the term
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 755Introduction vi
ip these are tips that relate to the exam Tey cover common pitalls based on the authorsrsquo experiences o their students and give you things to be wary o or to remember in order toscore marks in the exam Please note that this advice is not rom the University of CambridgeInternational Examinations Syndicate and they bear no responsibility or any such advice given
Te accompanying student CD-ROM at the back o the coursebook includes
A lsquocoverage gridrsquo to map the contents o the syllabus to the topics and chapters in thebullcoursebook
A lsquoCalculator supportrsquo chapter Tis chapter covers the main uses o calculators thatbullstudents seem to struggle with and includes some worksheets to provide practice at usingyour calculator in these situations
RevisionbullCore revision worksheets (and answers) provide extra exercises or each chapter o thebullbook Tese worksheets contain only content rom the Core syllabus
Extended revision worksheets (and answers) provide extra exercises or each chapterbullo the book Tese worksheets contain the same questions as the Core worksheets inaddition to some more challenging questions and questions to cover content unique
to the Extended syllabus Students are encouraged to do some (i not all) o the lsquoCorersquoquestions on these worksheets as well as the Extended ones (shaded) in order to ullyrevise the course I time is limited you might 1047297nd it easier to pick two or three lsquoCorersquoquestions to do beore moving on to the lsquoExtendedrsquo questions
Quick revision tests ndash these are interactive questions in the orm o multiple choice drbulland drop or hide and reveal Tey are quick-1047297re questions to test yoursel in a differenmedium to pen and paper and to get you thinking on the spot Tey cover the Corecontent with only a ew additional screens being speci1047297c to the Extended course Teris at least one activity or each chapter Students are recommended to use the Revisioworksheets for a more comprehensive revision exercise
Worked solutions ndash these are interactive hide and reveal screens showing workedbullsolutions to some o the end o chapter examination practice questions Some o thesewill be lsquoExam-stylersquo and some will be lsquoPast paperrsquo questions but all will be taken romthe end o the chapter Tere will be at least one or each chapter Te screen includesthe question and the answer but also includes a series o lsquoCluersquo or lsquoiprsquo boxes Te lsquoCluboxes can be clicked on to reveal a clue to help the student i they are struggling withhow to approach the question Te lsquoiprsquo boxes contain tips relating to the exam just likthe lsquoiprsquo boxes in the coursebook
Also in the Cambridge IGCSE Mathematics series are two Practice Books ndash one or Core and onor Extended ndash to offer students targeted practice Tese ollow the chapters and topics o thecoursebook including additional exercises or those who want more practice Tese too includlsquoHintsrsquo and lsquoipsrsquo to help with tricky topics
It is essential that youremember to work outboth unknowns Every
pair o simultaneous linearequations will have a pairo solutions
Tip
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 855Acknowledgements
AcknowledgementsTe authors and publishers acknowledge the following sources of copyright material and are grateful for the permissionsgranted
Past paper examination questions are reproduced by permission o University o Cambridge International Examinations
Cover image Seamus DitmeyerAlamy p 1 copy sanderderwildecom p 13 Dmitry LavruhinShutterstock p 13 HadriannShutterstop 13 Jason CoxShutterstock p 13 Ruslan NabiyevShutterstock p 46 IvangottShutterstock p 47 Claudio Baldini Shutterstock pakiyokoShutterstock p 73 INSAGOShutterstock p 98 copy Te rustees o the British Museum p 119 Wikipedia p 128 FrancescoDazziShutterstock p 164 North Wind Picture ArchiveAlamy p 148 Paolo GiantiShutterstock pp 153 341 487 533 iStockphotTinkstock p 155 Opachevsky IrinaShutterstock p 156 Chad LittlejohnShutterstock p 159 sahua dShutterstock p 206 PhotoscomTinkstock pp 223 419 428 Mike van der Wold p 235 Pics1047297veShutterstock p 250 Vladislav Gur1047297nkelShutterstock p 259Mike an CShutterstock p 261 SuzanShutterstock p 261 R-studioShutterstock p 264 Galyna AndrushkoShutterstock p 29Gustavo Miguel FernandesShutterstock p 351 Stephanie FrayShutterstock p 375 Kristina PostnikovaShutterstock p 397 ConnBrosShutterstock p 441 Philippe WojazerAPPress Association Images
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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Contentsiv
Chapter 13 Understanding measurement
131 Understanding units 251
132 Time 253
133 Upper and lower bounds 257
134 Conversion graphs 262
135 More money 264
Chapter 14 Further solving of equations andinequalities
141 Simultaneous linear equations 268
142 Linear inequalities 275
143 Regions in a plane 279
144 Linear programming 284
145 Completing the square 286
146 Quadratic formula 287
147 Factorising quadratics where the coefficient
of lsquo x 2lsquos is not 1 289
148 Algebraic fractions 291
Chapter 15 Scale drawings bearings andtrigonometry
151 Scale Drawings 3
152 Bearings 3
153 Understanding the tangent cosine
and sine ratios 3
154 Solving problems usingtrigonometry 3
155 Angles between 90deg and 180deg 3
156 The sine and cosine rules 3
157 Area of a triangle 3
158 Trigonometry in three-dimensions 3
Chapter 16 Scatter diagramsand correlation161 Introduction to bivariate data 3
Unit 4
Unit 5
Chapter 17 Managing money
171 Earning money 352
172 Borrowing and investing money 357
173 Buying and selling 363
Chapter 18 Curved graphs
181 Plotting quadratic graphs (the parabola) 371
182 Plotting reciprocal graphs (the hyperbola) 375
183 Using graphs to solve quadratic equations 377
184 Using graphs to solve simultaneous linear
and non-linear equations 379
185 Other non-linear graphs 381
186 Finding the gradient of a curve 390
Chapter 19 Symmetry and loci191 Symmetry in two-dimensions 3192 Symmetry in three-dimensions 4193 Symmetry properties of circles 4194 Angle relationships in circles 4195 Locus 4
Chapter 20 Histograms and frequency distributiondiagrams
201 Histograms 4
202 Cumulative frequency 4
Unit 6
Chapter 21 Ratio rate and proportion
211 Working with ratio 442
212 Ratio and scale 446
213 Rates 450
214 Kinematic graphs 452
215 Proportion 460
216 Direct and inverse proportion in
algebraic terms 463
217 Increasing and decreasing amounts
by a given ratio 467
Chapter 22 More equations formulae andfunctions
221 Setting up equations to solve problems 472
222 Using and transforming formulae 474
223 Functions and function notation 477
Chapter 23 Transformations and matrices
231 Simple plane transformations 4
232 Vectors 5
233 Further transformations 5
234 Matrices and matrix transformation 5
235 Matrices and transformations 5
Chapter 24 Probability using tree diagrams
241 Using tree diagrams to show outcomes 5
242 Calculating probability from tree diagrams 5
Examination practice structured question for Unit 4-6 5
Exercise Answers 5
Glossary 6
Index 6
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 655Introduction
IntroductionTis highly illustrated coursebook covers the complete Cambridge IGCSE Mathematics (0580syllabus Core and Extended material is combined in one book offering a one-stop-shop or
all students and teachers Useul hints are included in the margins or students needing moresupport leaving the narrative clear and to the point Te material required or the Extendedcourse is clearly marked using colour panels and these students are given access to the parts othe Core syllabus they need without having to use an additional book
Te coursebook has been written with a clear progression rom start to 1047297nish with some laterchapters requiring knowledge learnt in earlier chapters Tere are useul signposts throughouthe coursebook that link the content o the chapters allowing the individual to ollow their owcourse through the book where the content in one chapter might require knowledge rom aprevious chapter a comment is included in a lsquoRewindrsquo box and where content will be coveredmore detail later on in the coursebook a comment is included in a lsquoFast orwardrsquo box Exampo both are included here
Worked examples are used throughout to demonstrate each method using typical workings a
thought processes Tese present the methods to the students in a practical and easy-to-ollowway that minimises the need or lengthy explanations
Tere is plenty o practice offered via lsquodrillrsquo exercises throughout each chapter Te exercisesare progressive questions which allow the student to practise methods that have just beenintroduced At the end o each chapter there are lsquoExam-stylersquo questions and lsquoPast paperrsquoquestions Te exam-style questions have been written by the authors in the style o questionson exam papers Te past paper questions are real questions taken rom past exam papers Tend o chapter questions typically re1047298ect the lsquoshortrsquo Paper 1 (Core) and Paper 2 (Extended)questions though you will 1047297nd some more structured ones in there as well Te answers to alo these questions are supplied at the back o the book allowing sel- andor class- assessmenStudents can assess their progress as they go along choosing to do more or less practise asrequired
Te lsquosuggestedrsquo progression through the coursebook is or Units 1-3 to be covered in the1047297rst year o both courses and Units 4-6 to be covered in the second year o both coursesOn this basis there is mixed exam practice at the end o Unit 3 and the end o Unit 6 Tis ishowever only a suggested structure and the course can be taught in various different waysthe signposting throughout the coursebook means that it can be used alongside any order oteaching Te end o Unit questions represent the longer answer lsquostructuredrsquo questions o Pap(Core) and Paper 4 (Extended) exam papers and will use a combination o methods rom acrall relevant chapters As with the end o chapter questions these are a mixture o lsquoExam-stylersquoand lsquoPast paperrsquo questions Te answers to these questions are on the eacherrsquos resource so thathey can be used in classroom tests or or homework i desired
Te coursebook also comes with a glossary to provide a de1047297nition or important tricky term
Helpul guides in the margin o the book include
Hints these are general comments to remind you o important or key inormation that is use
to tackle an exercise or simply useul to know Tey ofen provide extra inormation or suppoin potentially tricky topics
You learned how to plot lines from
equations in chapter 10
REWIND
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or otheritems that are often placed inside
curly brackets
FAST FORWARD
Remember lsquocoefficientrsquo is the number in the term
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 755Introduction vi
ip these are tips that relate to the exam Tey cover common pitalls based on the authorsrsquo experiences o their students and give you things to be wary o or to remember in order toscore marks in the exam Please note that this advice is not rom the University of CambridgeInternational Examinations Syndicate and they bear no responsibility or any such advice given
Te accompanying student CD-ROM at the back o the coursebook includes
A lsquocoverage gridrsquo to map the contents o the syllabus to the topics and chapters in thebullcoursebook
A lsquoCalculator supportrsquo chapter Tis chapter covers the main uses o calculators thatbullstudents seem to struggle with and includes some worksheets to provide practice at usingyour calculator in these situations
RevisionbullCore revision worksheets (and answers) provide extra exercises or each chapter o thebullbook Tese worksheets contain only content rom the Core syllabus
Extended revision worksheets (and answers) provide extra exercises or each chapterbullo the book Tese worksheets contain the same questions as the Core worksheets inaddition to some more challenging questions and questions to cover content unique
to the Extended syllabus Students are encouraged to do some (i not all) o the lsquoCorersquoquestions on these worksheets as well as the Extended ones (shaded) in order to ullyrevise the course I time is limited you might 1047297nd it easier to pick two or three lsquoCorersquoquestions to do beore moving on to the lsquoExtendedrsquo questions
Quick revision tests ndash these are interactive questions in the orm o multiple choice drbulland drop or hide and reveal Tey are quick-1047297re questions to test yoursel in a differenmedium to pen and paper and to get you thinking on the spot Tey cover the Corecontent with only a ew additional screens being speci1047297c to the Extended course Teris at least one activity or each chapter Students are recommended to use the Revisioworksheets for a more comprehensive revision exercise
Worked solutions ndash these are interactive hide and reveal screens showing workedbullsolutions to some o the end o chapter examination practice questions Some o thesewill be lsquoExam-stylersquo and some will be lsquoPast paperrsquo questions but all will be taken romthe end o the chapter Tere will be at least one or each chapter Te screen includesthe question and the answer but also includes a series o lsquoCluersquo or lsquoiprsquo boxes Te lsquoCluboxes can be clicked on to reveal a clue to help the student i they are struggling withhow to approach the question Te lsquoiprsquo boxes contain tips relating to the exam just likthe lsquoiprsquo boxes in the coursebook
Also in the Cambridge IGCSE Mathematics series are two Practice Books ndash one or Core and onor Extended ndash to offer students targeted practice Tese ollow the chapters and topics o thecoursebook including additional exercises or those who want more practice Tese too includlsquoHintsrsquo and lsquoipsrsquo to help with tricky topics
It is essential that youremember to work outboth unknowns Every
pair o simultaneous linearequations will have a pairo solutions
Tip
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 855Acknowledgements
AcknowledgementsTe authors and publishers acknowledge the following sources of copyright material and are grateful for the permissionsgranted
Past paper examination questions are reproduced by permission o University o Cambridge International Examinations
Cover image Seamus DitmeyerAlamy p 1 copy sanderderwildecom p 13 Dmitry LavruhinShutterstock p 13 HadriannShutterstop 13 Jason CoxShutterstock p 13 Ruslan NabiyevShutterstock p 46 IvangottShutterstock p 47 Claudio Baldini Shutterstock pakiyokoShutterstock p 73 INSAGOShutterstock p 98 copy Te rustees o the British Museum p 119 Wikipedia p 128 FrancescoDazziShutterstock p 164 North Wind Picture ArchiveAlamy p 148 Paolo GiantiShutterstock pp 153 341 487 533 iStockphotTinkstock p 155 Opachevsky IrinaShutterstock p 156 Chad LittlejohnShutterstock p 159 sahua dShutterstock p 206 PhotoscomTinkstock pp 223 419 428 Mike van der Wold p 235 Pics1047297veShutterstock p 250 Vladislav Gur1047297nkelShutterstock p 259Mike an CShutterstock p 261 SuzanShutterstock p 261 R-studioShutterstock p 264 Galyna AndrushkoShutterstock p 29Gustavo Miguel FernandesShutterstock p 351 Stephanie FrayShutterstock p 375 Kristina PostnikovaShutterstock p 397 ConnBrosShutterstock p 441 Philippe WojazerAPPress Association Images
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 655Introduction
IntroductionTis highly illustrated coursebook covers the complete Cambridge IGCSE Mathematics (0580syllabus Core and Extended material is combined in one book offering a one-stop-shop or
all students and teachers Useul hints are included in the margins or students needing moresupport leaving the narrative clear and to the point Te material required or the Extendedcourse is clearly marked using colour panels and these students are given access to the parts othe Core syllabus they need without having to use an additional book
Te coursebook has been written with a clear progression rom start to 1047297nish with some laterchapters requiring knowledge learnt in earlier chapters Tere are useul signposts throughouthe coursebook that link the content o the chapters allowing the individual to ollow their owcourse through the book where the content in one chapter might require knowledge rom aprevious chapter a comment is included in a lsquoRewindrsquo box and where content will be coveredmore detail later on in the coursebook a comment is included in a lsquoFast orwardrsquo box Exampo both are included here
Worked examples are used throughout to demonstrate each method using typical workings a
thought processes Tese present the methods to the students in a practical and easy-to-ollowway that minimises the need or lengthy explanations
Tere is plenty o practice offered via lsquodrillrsquo exercises throughout each chapter Te exercisesare progressive questions which allow the student to practise methods that have just beenintroduced At the end o each chapter there are lsquoExam-stylersquo questions and lsquoPast paperrsquoquestions Te exam-style questions have been written by the authors in the style o questionson exam papers Te past paper questions are real questions taken rom past exam papers Tend o chapter questions typically re1047298ect the lsquoshortrsquo Paper 1 (Core) and Paper 2 (Extended)questions though you will 1047297nd some more structured ones in there as well Te answers to alo these questions are supplied at the back o the book allowing sel- andor class- assessmenStudents can assess their progress as they go along choosing to do more or less practise asrequired
Te lsquosuggestedrsquo progression through the coursebook is or Units 1-3 to be covered in the1047297rst year o both courses and Units 4-6 to be covered in the second year o both coursesOn this basis there is mixed exam practice at the end o Unit 3 and the end o Unit 6 Tis ishowever only a suggested structure and the course can be taught in various different waysthe signposting throughout the coursebook means that it can be used alongside any order oteaching Te end o Unit questions represent the longer answer lsquostructuredrsquo questions o Pap(Core) and Paper 4 (Extended) exam papers and will use a combination o methods rom acrall relevant chapters As with the end o chapter questions these are a mixture o lsquoExam-stylersquoand lsquoPast paperrsquo questions Te answers to these questions are on the eacherrsquos resource so thathey can be used in classroom tests or or homework i desired
Te coursebook also comes with a glossary to provide a de1047297nition or important tricky term
Helpul guides in the margin o the book include
Hints these are general comments to remind you o important or key inormation that is use
to tackle an exercise or simply useul to know Tey ofen provide extra inormation or suppoin potentially tricky topics
You learned how to plot lines from
equations in chapter 10
REWIND
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or otheritems that are often placed inside
curly brackets
FAST FORWARD
Remember lsquocoefficientrsquo is the number in the term
copy Cambridge University Press 2012
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 755Introduction vi
ip these are tips that relate to the exam Tey cover common pitalls based on the authorsrsquo experiences o their students and give you things to be wary o or to remember in order toscore marks in the exam Please note that this advice is not rom the University of CambridgeInternational Examinations Syndicate and they bear no responsibility or any such advice given
Te accompanying student CD-ROM at the back o the coursebook includes
A lsquocoverage gridrsquo to map the contents o the syllabus to the topics and chapters in thebullcoursebook
A lsquoCalculator supportrsquo chapter Tis chapter covers the main uses o calculators thatbullstudents seem to struggle with and includes some worksheets to provide practice at usingyour calculator in these situations
RevisionbullCore revision worksheets (and answers) provide extra exercises or each chapter o thebullbook Tese worksheets contain only content rom the Core syllabus
Extended revision worksheets (and answers) provide extra exercises or each chapterbullo the book Tese worksheets contain the same questions as the Core worksheets inaddition to some more challenging questions and questions to cover content unique
to the Extended syllabus Students are encouraged to do some (i not all) o the lsquoCorersquoquestions on these worksheets as well as the Extended ones (shaded) in order to ullyrevise the course I time is limited you might 1047297nd it easier to pick two or three lsquoCorersquoquestions to do beore moving on to the lsquoExtendedrsquo questions
Quick revision tests ndash these are interactive questions in the orm o multiple choice drbulland drop or hide and reveal Tey are quick-1047297re questions to test yoursel in a differenmedium to pen and paper and to get you thinking on the spot Tey cover the Corecontent with only a ew additional screens being speci1047297c to the Extended course Teris at least one activity or each chapter Students are recommended to use the Revisioworksheets for a more comprehensive revision exercise
Worked solutions ndash these are interactive hide and reveal screens showing workedbullsolutions to some o the end o chapter examination practice questions Some o thesewill be lsquoExam-stylersquo and some will be lsquoPast paperrsquo questions but all will be taken romthe end o the chapter Tere will be at least one or each chapter Te screen includesthe question and the answer but also includes a series o lsquoCluersquo or lsquoiprsquo boxes Te lsquoCluboxes can be clicked on to reveal a clue to help the student i they are struggling withhow to approach the question Te lsquoiprsquo boxes contain tips relating to the exam just likthe lsquoiprsquo boxes in the coursebook
Also in the Cambridge IGCSE Mathematics series are two Practice Books ndash one or Core and onor Extended ndash to offer students targeted practice Tese ollow the chapters and topics o thecoursebook including additional exercises or those who want more practice Tese too includlsquoHintsrsquo and lsquoipsrsquo to help with tricky topics
It is essential that youremember to work outboth unknowns Every
pair o simultaneous linearequations will have a pairo solutions
Tip
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 855Acknowledgements
AcknowledgementsTe authors and publishers acknowledge the following sources of copyright material and are grateful for the permissionsgranted
Past paper examination questions are reproduced by permission o University o Cambridge International Examinations
Cover image Seamus DitmeyerAlamy p 1 copy sanderderwildecom p 13 Dmitry LavruhinShutterstock p 13 HadriannShutterstop 13 Jason CoxShutterstock p 13 Ruslan NabiyevShutterstock p 46 IvangottShutterstock p 47 Claudio Baldini Shutterstock pakiyokoShutterstock p 73 INSAGOShutterstock p 98 copy Te rustees o the British Museum p 119 Wikipedia p 128 FrancescoDazziShutterstock p 164 North Wind Picture ArchiveAlamy p 148 Paolo GiantiShutterstock pp 153 341 487 533 iStockphotTinkstock p 155 Opachevsky IrinaShutterstock p 156 Chad LittlejohnShutterstock p 159 sahua dShutterstock p 206 PhotoscomTinkstock pp 223 419 428 Mike van der Wold p 235 Pics1047297veShutterstock p 250 Vladislav Gur1047297nkelShutterstock p 259Mike an CShutterstock p 261 SuzanShutterstock p 261 R-studioShutterstock p 264 Galyna AndrushkoShutterstock p 29Gustavo Miguel FernandesShutterstock p 351 Stephanie FrayShutterstock p 375 Kristina PostnikovaShutterstock p 397 ConnBrosShutterstock p 441 Philippe WojazerAPPress Association Images
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 755Introduction vi
ip these are tips that relate to the exam Tey cover common pitalls based on the authorsrsquo experiences o their students and give you things to be wary o or to remember in order toscore marks in the exam Please note that this advice is not rom the University of CambridgeInternational Examinations Syndicate and they bear no responsibility or any such advice given
Te accompanying student CD-ROM at the back o the coursebook includes
A lsquocoverage gridrsquo to map the contents o the syllabus to the topics and chapters in thebullcoursebook
A lsquoCalculator supportrsquo chapter Tis chapter covers the main uses o calculators thatbullstudents seem to struggle with and includes some worksheets to provide practice at usingyour calculator in these situations
RevisionbullCore revision worksheets (and answers) provide extra exercises or each chapter o thebullbook Tese worksheets contain only content rom the Core syllabus
Extended revision worksheets (and answers) provide extra exercises or each chapterbullo the book Tese worksheets contain the same questions as the Core worksheets inaddition to some more challenging questions and questions to cover content unique
to the Extended syllabus Students are encouraged to do some (i not all) o the lsquoCorersquoquestions on these worksheets as well as the Extended ones (shaded) in order to ullyrevise the course I time is limited you might 1047297nd it easier to pick two or three lsquoCorersquoquestions to do beore moving on to the lsquoExtendedrsquo questions
Quick revision tests ndash these are interactive questions in the orm o multiple choice drbulland drop or hide and reveal Tey are quick-1047297re questions to test yoursel in a differenmedium to pen and paper and to get you thinking on the spot Tey cover the Corecontent with only a ew additional screens being speci1047297c to the Extended course Teris at least one activity or each chapter Students are recommended to use the Revisioworksheets for a more comprehensive revision exercise
Worked solutions ndash these are interactive hide and reveal screens showing workedbullsolutions to some o the end o chapter examination practice questions Some o thesewill be lsquoExam-stylersquo and some will be lsquoPast paperrsquo questions but all will be taken romthe end o the chapter Tere will be at least one or each chapter Te screen includesthe question and the answer but also includes a series o lsquoCluersquo or lsquoiprsquo boxes Te lsquoCluboxes can be clicked on to reveal a clue to help the student i they are struggling withhow to approach the question Te lsquoiprsquo boxes contain tips relating to the exam just likthe lsquoiprsquo boxes in the coursebook
Also in the Cambridge IGCSE Mathematics series are two Practice Books ndash one or Core and onor Extended ndash to offer students targeted practice Tese ollow the chapters and topics o thecoursebook including additional exercises or those who want more practice Tese too includlsquoHintsrsquo and lsquoipsrsquo to help with tricky topics
It is essential that youremember to work outboth unknowns Every
pair o simultaneous linearequations will have a pairo solutions
Tip
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 855Acknowledgements
AcknowledgementsTe authors and publishers acknowledge the following sources of copyright material and are grateful for the permissionsgranted
Past paper examination questions are reproduced by permission o University o Cambridge International Examinations
Cover image Seamus DitmeyerAlamy p 1 copy sanderderwildecom p 13 Dmitry LavruhinShutterstock p 13 HadriannShutterstop 13 Jason CoxShutterstock p 13 Ruslan NabiyevShutterstock p 46 IvangottShutterstock p 47 Claudio Baldini Shutterstock pakiyokoShutterstock p 73 INSAGOShutterstock p 98 copy Te rustees o the British Museum p 119 Wikipedia p 128 FrancescoDazziShutterstock p 164 North Wind Picture ArchiveAlamy p 148 Paolo GiantiShutterstock pp 153 341 487 533 iStockphotTinkstock p 155 Opachevsky IrinaShutterstock p 156 Chad LittlejohnShutterstock p 159 sahua dShutterstock p 206 PhotoscomTinkstock pp 223 419 428 Mike van der Wold p 235 Pics1047297veShutterstock p 250 Vladislav Gur1047297nkelShutterstock p 259Mike an CShutterstock p 261 SuzanShutterstock p 261 R-studioShutterstock p 264 Galyna AndrushkoShutterstock p 29Gustavo Miguel FernandesShutterstock p 351 Stephanie FrayShutterstock p 375 Kristina PostnikovaShutterstock p 397 ConnBrosShutterstock p 441 Philippe WojazerAPPress Association Images
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 855Acknowledgements
AcknowledgementsTe authors and publishers acknowledge the following sources of copyright material and are grateful for the permissionsgranted
Past paper examination questions are reproduced by permission o University o Cambridge International Examinations
Cover image Seamus DitmeyerAlamy p 1 copy sanderderwildecom p 13 Dmitry LavruhinShutterstock p 13 HadriannShutterstop 13 Jason CoxShutterstock p 13 Ruslan NabiyevShutterstock p 46 IvangottShutterstock p 47 Claudio Baldini Shutterstock pakiyokoShutterstock p 73 INSAGOShutterstock p 98 copy Te rustees o the British Museum p 119 Wikipedia p 128 FrancescoDazziShutterstock p 164 North Wind Picture ArchiveAlamy p 148 Paolo GiantiShutterstock pp 153 341 487 533 iStockphotTinkstock p 155 Opachevsky IrinaShutterstock p 156 Chad LittlejohnShutterstock p 159 sahua dShutterstock p 206 PhotoscomTinkstock pp 223 419 428 Mike van der Wold p 235 Pics1047297veShutterstock p 250 Vladislav Gur1047297nkelShutterstock p 259Mike an CShutterstock p 261 SuzanShutterstock p 261 R-studioShutterstock p 264 Galyna AndrushkoShutterstock p 29Gustavo Miguel FernandesShutterstock p 351 Stephanie FrayShutterstock p 375 Kristina PostnikovaShutterstock p 397 ConnBrosShutterstock p 441 Philippe WojazerAPPress Association Images
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 1055Unit 1 Number
1 Reviewing numberconcepts
In this chapter youwill learn how to
identify and classifybulldifferent types of numbers
find common factors andbullcommon multiples ofnumbers
write numbers as productsbullof their prime factors
calculate squares squarebullroots cubes and cube rootsof numbers
work with integers used inbullreal-life situations
revise the basic rules forbulloperating with numbers
perform basic calculationsbull using mental methods andwith a calculator
Natural numberbullIntegerbullPrime numberbullSymbolbullMultiplebullFactorbullComposite numbers
bull Prime factorbullSquare rootbullCubebullDirected numbersbullBODMASbull
Key words
Our modern number system is called the Hindu-Arabic system because it was developed byHindus and spread by Arab traders who brought it with them when they moved to differentplaces in the world Te Hindu-Arabic system is decimal Tis means it uses place value basedon powers o ten Any number at all including decimals and ractions can be written usingplace value and the digits rom 0 to 9
Tis statue is a replica of a 22 000-year-old bone found in the Congo Te real bone is only 10 cm long and
is carved with groups of notches that represent numbers One column lists the prime numbers from 10 to
It is one of the earliest examples of a number system using tallies
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number concepts
Unit 1 Number2
11 Different types of numbersMake sure you know the correct mathematical words or the types o numbers in the table
Number De1047297nition Example
Natural number Any whole number rom 1 to in1047297nitysometimes called lsquocounting numbersrsquo 0 is notincluded
1 2 3 4 5
Odd number A whole number that cannot be dividedexactly by 2
1 3 5 7
Even number A whole number that can be dividedexactly by 2
2 4 6 8
Integer Any o the negative and positive wholenumbers including zero
minus3 minus2 minus1 0 1 23
Prime number A whole number greater than 1 which hasonly two actors the number itsel and 1
2 3 5 7 11
Square number Te product obtained when an integer is
multiplied by itsel
1 4 9 16
Fraction A number representing parts o a wholenumber can be written as a common (vulgar)raction in the orm o a
b or as a decimal usingthe decimal point
05 02 008 17
Exercise 11 1 Here is a set o numbers minus4 minus1 0 075 3 4 6 11 16 19 25
List the numbers rom this set that are
(a) natural numbers (b) even numbers (c) odd numbers(d) integers (e) negative integers (f) ractions(g) square numbers (h) prime numbers (i) neither square nor prime
2 List
(a) the next our odd numbers afer 107(b) our consecutive even numbers between 2008 and 2030(c) all odd numbers between 993 and 1007(d) the 1047297rst 1047297ve square numbers(e) our decimal ractions that are smaller than 05(f) our vulgar ractions that are greater than but smaller than 4
3 State whether the ollowing will be odd or even
(a) the sum o two odd numbers(b) the sum o two even numbers(c) the sum o an odd and an even number(d) the square o an odd number(e) the square o an even number(f) an odd number multiplied by an even number
You will learn much more about
sets in chapter 9 For now just think
of a set as a list of numbers or other
items that are often placed insidecurly brackets
FAST FORWARD
Remember that a sum is the
result of an addition The term isoften used for any calculation inearly mathematics but its meaningis very specific at this level
You should already be familiarwith most of the concepts in thischapter It is included here so that
you can revise the concepts andcheck that you remember them
You will learn about the difference
between rational and irrational
numbers in chapter 9
FAST FORWARD
Find the lsquoproductrsquo means lsquomultiplyrsquoSo the product of 3 and 4 is 12ie 3 times 4 = 12
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
Living maths
4 Tere are many other types o numbers Find out what these numbers are and give anexample o each
(a) Perect numbers(b) Palindromic numbers(c) Narcissistic numbers (In other words numbers that love themselves)
Using symbols to link numbersMathematicians use numbers and symbols to write mathematical inormation in the shortestclearest way possible
You have used the operation symbols + minus times and divide since you started school Now you will alsouse the symbols given in the margin below to write mathematical statements
Exercise 12 1 Rewrite each o these statements using mathematical symbols
(a) 19 is less than 45(b) 12 plus 18 is equal to 30(c) 05 is equal to
(d) 08 is not equal to 80(e) minus34 is less than 2 times minus16(f) thereore the number x equals the square root o 72(g) a number (x ) is less than or equal to negative 45(h) π is approximately equal to 314(i) 51 is greater than 501(j) the sum o 3 and 4 is not equal to the product o 3 and 4(k) the difference between 12 and minus12 is greater than 12(l) the sum o minus12 and minus24 is less than 0(m) the product o 12 and a number (x ) is approximately minus40
2 Say whether these mathematical statements are true or alse
(a) 0599 gt 60 (b) 5 times 1999 asymp 10 000
(c) 1 110= (d) 62 + 43 = 43 + 62(e) 20 times 9 ge 21 times 8 (f) 60 = 6(g) minus12 gt minus4 (h) 199 le 20(i) 1000 gt 199 times 5 (j) 16 4(k) 35 times 5 times 2 ne 350 (l) 20 divide 4 = 5 divide 20(m) 20 minus 4 ne 4 minus 20 (n) 20 times 4 ne 4 times 20
3 Work with a partner
(a) Look at the symbols used on the keys o your calculator Say what each one meansin words
(b) List any symbols that you do not know ry to 1047297nd out what each one means
12 Multiples and factorsYou can think o the multiples o a number as the lsquotimes tablersquo or that number For example tmultiples o 3 are 3 times 1 = 3 3 times 2 = 6 3 times 3 = 9 and so on
MultiplesA multiple o a number is ound when you multiply that number by a positive integer Te 1047297rmultiple o any number is the number itsel (the number multiplied by 1)
= is equal to
ne is not equal to
asymp
is approximately equal tolt is less than
le is less than or equal to
gt is greater than
ge is greater than or equal to
there4 therefore
the square root of
Remember that the differencebetween two numbers is the result
of a subtraction The order of thesubtraction matters
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number concepts
Unit 1 Number4
Worked example 1
(a) What are the first three multiples of 12
(b) Is 300 a multiple of 12
(a) 12 24 36 To find these multiply 12 by 1 2 and then 3
12 times 1 = 12
12 times 2 = 2412 times 3 = 36
(b) Yes 300 is a multiple of 12 To find out divide 300 by 12 If it goes exactly then 300 is a multiple of 12
300 divide 12 = 25
Exercise 13 1 List the 1047297rst 1047297ve multiples o
(a) 2 (b) 3 (c) 5 (d) 8(e) 9 (f) 10 (g) 12 (h) 100
2 Use a calculator to 1047297nd and list the 1047297rst ten multiples o
(a) 29 (b) 44 (c) 75 (d) 114(e) 299 (f) 350 (g) 1012 (h) 9123
3 List
(a) the multiples o 4 between 29 and 53(b) the multiples o 50 less than 400(c) the multiples o 100 between 4000 and 5000
4 Here are 1047297ve numbers 576 396 354 792 1164 Which o these are multiples o 12
5 Which o the ollowing numbers are not multiples o 27
(a) 324 (b) 783 (c) 816 (d) 837 (e) 1116
The lowest common multiple (LCM)
Te lowest common multiple o two or more numbers is the smallest number that is a multipleo all the given numbers
Worked example 2
Find the lowest common multiple of 4 and 7
M4 = 4 8 12 16 20 24 28 32
M7 = 7 14 21 28 35 42
LCM = 28
List several multiples of 4 (Note M4 means multiples of 4)
List several multiples of 7
Find the lowest number that appears in both sets This is the LCM
Exercise 14 1 Find the LCM o
Later in this chapter you will see
how prime factors can be used to
find LCMs
FAST FORWARD (a) 2 and 5 (b) 8 and 10 (c) 6 and 4(d) 3 and 9 (e) 35 and 55 (f) 6 and 11(g) 2 4 and 8 (h) 4 5 and 6 (i) 6 8 and 9(j) 1 3 and 7 (k) 4 5 and 8 (l) 3 4 and 18
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
2 Is it possible to 1047297nd the highest common multiple o two or more numbersGive a reason or your answer
FactorsA factor is a number that divides exactly into another number with no remainder For examp2 is a actor o 16 because it goes into 16 exactly 8 times 1 is a actor o every number Telargest actor o any number is the number itsel
To list the factors in numerical ordergo down the left side and then upthe right side of the factor pairsRemember not to repeat factors
Worked example 3
Find the factors of
(a) 12 (b) 25 (c) 110
(a) F 12
= 1 2 3 4 6 12 Find pairs of numbers that multiply to give 12
1 times 12
2 times 6
3 times 4
Write the factors in numerical order
(b) F 25 = 1 5 25 1 times 255 times 5
Do not repeat the 5
(c) F 110
= 1 2 5 10 11 22 55 110 1 times 110
2 times 55
5 times 22
10 times 11
F 12
means the factors of 12
Exercise 15 1 List all the actors o
(a) 4 (b) 5 (c) 8 (d) 11 (e) 18(f) 12 (g) 35 (h) 40 (i) 57 (j) 90(k) 100 (l) 132 (m) 160 (n) 153 (o) 360
2 Which number in each set is not a actor o the given number
(a) 14 1 2 4 7 14(b) 15 1 3 5 15 45(c) 21 1 3 7 14 21(d) 33 1 3 11 22 33(e) 42 3 6 7 8 14
Later in this chapter you will learn
more about divisibility tests and
how to use these to decide whetheror not one number is a factor of
another
FAST FORWARD3 State true or alse in each case
(a) 3 is a actor o 313 (b) 9 is a actor o 99
(c) 3 is a actor o 300 (d) 2 is a actor o 300(e) 2 is a actor o 122 488 (f) 12 is a actor o 60(g) 210 is a actor o 210 (h) 8 is a actor o 420
4 What is the smallest actor and the largest actor o any number
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number concepts
Unit 1 Number6
The highest common factor (HCF)
Te highest common actor o two or more numbers is the highest number that is a actor o althe given numbers
Worked example 4
Find the HCF of 8 and 24
F 8 = 1 2 4 8
F 24
= 1 2 3 4 6 8 12 24
HCF = 8
List the factors of each number
Underline factors that appear in both sets
Pick out the highest underlined factor (HCF)
Exercise 16 1 Find the HCF o each pair o numbers
(a) 3 and 6 (b) 24 and 16 (c) 15 and 40 (d) 42 and 70(e) 32 and 36 (f) 26 and 36 (g) 22 and 44 (h) 42 and 48
2 Find the HCF o each group o numbers
(a) 3 9 and 15 (b) 36 63 and 84 (c) 22 33 and 121
3 Not including the actor provided 1047297nd two numbers that have
(a) an HCF o 2 (b) an HCF o 6
4 What is the HCF o two different prime numbers Give a reason or your answer
Living maths
5 Simeon has two lengths o rope One piece is 72 metres long and the other is 90 metres longHe wants to cut both lengths o rope into the longest pieces o equal length possible Howlong should the pieces be
6 Ms Sanchez has 40 canvases and 100 tubes o paint to give to the students in her art group
What is the largest number o students she can have i she gives each student an equalnumber o canvasses and an equal number o tubes o paint
7 Indira has 300 blue beads 750 red beads and 900 silver beads She threads these beads tomake wire bracelets Each bracelet must have the same number and colour o beads Whatis the maximum number o bracelets she can make with these beads
13 Prime numbersPrime numbers have exactly two actors one and the number itsel
Composite numbers have more than two actors
Te number 1 has only one actor so it is not prime and it is not composite
Finding prime numbersOver 2000 years ago a Greek mathematician called Eratosthenes made a simple tool or sortingout prime numbers Tis tool is called the lsquoSieve o Eratosthenesrsquo and the 1047297gure on page 7 showhow it works or prime numbers up to 100
You will learn how to find HCFs
by using prime factors later in the
chapter
FAST FORWARD
Word problems involving HCFusually involve splitting things intosmaller pieces or arranging thingsin equal groups or rows
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
11 12
21
31
41
5161
71
81
91
3
13
23
33
43
5363
73
83
93
4
14
24
34
44
5464
74
84
94
5
15
25
35
45
5565
75
85
95
6
16
26
36
46
5666
76
86
96
2
22
32
42
5262
72
82
92
7
17
27
37
47
5767
77
87
97
1 8
18
28
38
48
5868
78
88
98
9
19
29
39
49
5969
79
89
99
10
20
30
40
50
6070
80
90
100
Cross out 1 it is not prime
Circle 2 then cross out other
multiples of 2
Circle 3 then cross out other
multiples of 3
Circle the next available num
then cross out all its multiple
Repeat until all the numbers i
the table are either circled or
crossed out
The circled numbers are the
primes
You should try to memorisewhich numbers between 1 and100 are prime
Other mathematicians over the years have developed ways o 1047297nding larger and larger primenumbers Until 1955 the largest known prime number had less than 1000 digits Since the1970s and the invention o more and more powerul computers more and more prime numbhave been ound Te graph below shows the number o digits in the largest known primessince 1955
1955 1965 1975 1985 1995 2005 2015100
1000
10 000
100 000
10 000 000
1 000 000
100 000 000
Year
Number of digits in largest known prime number
against year found
Number
of digits
oday anyone can join the Great Internet Mersenne Prime Search Tis project links thousano home computers to search continuously or larger and larger prime numbers while thecomputer processors have spare capacity
Exercise 17 1 Which is the only even prime number
2 How many odd prime numbers are there less than 50
3 (a) List the composite numbers greater than our but less than 30
(b) ry to write each composite number on your list as the sum o two prime numbersFor example 6 = 3 + 3 and 8 = 3 + 5
4 win primes are pairs o prime numbers that differ by two List the twin prime pairs up to
A good knowledge of primes can
help when factorising quadratics in
chapter 10
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
copy Cambridge University Press 2012
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number concepts
Unit 1 Number8
5 Is 149 a prime number Explain how you decided
6 Super-prime numbers are prime numbers that stay prime each time you remove a digit(starting with the units) So 59 is a super-prime because when you remove 9 you are lef with which is also prime 239 is also a super-prime because when you remove 9 you are lef with 23which is prime and when you remove 3 you are lef with 2 which is prime
(a) Find two three-digit super-prime numbers less than 400(b) Can you 1047297nd a our-digit super-prime number less than 3000(c) Sondrarsquos telephone number is the prime number 987-6413 Is her phone number a
super-prime
Prime factorsPrime factors are the actors o a number that are also prime numbers
Every composite whole number can be broken down and written as the product o its prime actorsYou can do this using tree diagrams or using division Both methods are shown in worked example
Prime numbers only have twofactors 1 and the number itselfAs 1 is not a prime number donot include it when expressinga number as a product of primefactors
Choose the method that worksbest for you and stick to it Alwaysshow your method when usingprime factors
Worked example 5
Write the following numbers as the product of prime factors
(a) 36 (b) 48
Using a factor tree
36
123
3
2 2
4
36 = 2 times 2 times 3 times 3
48
124
32 2
2 2
4
48 = 2 times 2 times 2 times 2 times 3
Write the number as two
factors
If a factor is a prime
number circle it
If a factor is a composite
number split it into two
factors
Keep splitting until you endup with two primes
Write the primes in
ascending order with times
signs
Using division
3618931
2233
36 = 2 times 2 times 3 times 3
48
24
12
6
31
2
2
2
2
3
48 = 2 times 2 times 2 times 2 times 3
Divide by the smallest
prime number that will go
into the number exactly
Continue dividing using
the smallest prime number
that will go into your newanswer each time
Stop when you reach 1
Write the prime factors in
ascending order with times
signs
Whilst super-primenumbers are interestingthey are not on thesyllabus
Tip
Remember a product is the answerto a multiplication So if you write anumber as the product of its primefactors you are writing it usingmultiplication signs like this12 = 2 times 2 times 3
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
Exercise 18 1 Express the ollowing numbers as the product o prime actors
(a) 30 (b) 24 (c) 100 (d) 225 (e) 360(f) 504 (g) 650 (h) 1125 (i) 756 (j) 9240
Using prime factors to find the HCF and LCM
When you are working with larger numbers you can determine the HCF or LCM by expressineach number as a product o its prime actors
Worked example 6
Find the HCF of 168 and 180
168 = 2 times 2 times 2 times 3 times 7
180 = 2 times 2 times 3 times 3 times 5
2 times 2 times 3 = 12
HCF = 12
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the factors common to both numbers
Multiply these out to find the HCF
Worked example 7
Find the LCM of 72 and 120
72 = 2 times 2 times 2 times 3 times 3
120 = 2 times 2 times 2 times 3 times 5
2 times 2 times 2 times 3 times 3 times 5 = 360
LCM = 360
First express each number as a product of prime
factors Use tree diagrams or division to do this
Underline the largest set of multiples of each factor
List these and multiply them out to find the LCM
Exercise 19 1 Find the HCF o these numbers by means o prime actors
(a) 48 and 108 (b) 120 and 216 (c) 72 and 90 (d) 52 and 78(e) 100 and 125 (f) 154 and 88 (g) 546 and 624 (h) 95 and 120
2 Use prime actorisation to determine the LCM o
(a) 54 and 60 (b) 54 and 72 (c) 60 and 72 (d) 48 and 60(e) 120 and 180 (f) 95 and 150 (g) 54 and 90 (h) 90 and 120
3 Determine both the HCF and LCM o the ollowing numbers
(a) 72 and 108 (b) 25 and 200 (c) 95 and 120 (d) 84 and 60
Word problems involving LCMusually include repeating eventsYou may be asked how manyitems you need to lsquohave enoughrsquoor when something will happenagain at the same time
Living maths4 A radio station runs a phone-in competition or listeners Every 30th caller gets a ree airt
voucher and every 120th caller gets a ree mobile phone How many listeners must phonebeore one receives both an airtime voucher and a ree phone
5 Lee runs round a track in 12 minutes James runs round the same track in 18 minutes I tstart in the same place at the same time how many minutes will pass beore they both crothe start line together again
When you write your number asa product of primes group alloccurrences of the same primenumber together
You can also use prime factors to
find the square and cube roots
of numbers if you donrsquot have a
calculator You will deal with this in
more detail on page 11
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number concepts
Unit 1 Number10
Divisibility tests to find factors easilySometimes you want to know i a smaller number will divide into a larger one with noremainder In other words is the larger number divisible by the smaller one
Tese simple divisibility tests are useul or working this out
A number is exactly divisible by
2 i it ends with 0 2 4 6 or 8 (in other words is even)
3 i the sum o its digits is a multiple o 3 (can be divided by 3)
4 i the last two digits can be divided by 4
5 i it ends with 0 or 5
6 i it is divisible by both 2 and 3
8 i the last three digits are divisible by 8
9 i the sum o the digits is a multiple o 9 (can be divided by 9)
10 i the number ends in 0
Tere is no simple test or divisibility by 7 although multiples o 7 do have some interestingproperties that you can investigate on the internet
Exercise 110 23 65 92 10 104 70 500 21 64 798 1223
1 Look at the box o numbers above Which o these numbers are
(a) divisible by 5 (b) divisible by 8 (c) divisible by 3
2 Say whether the ollowing are true or alse
(a) 625 is divisible by 5 (b) 88 is divisible by 3(c) 640 is divisible by 6 (d) 346 is divisible by 4(e) 476 is divisible by 8 (f) 2340 is divisible by 9(g) 2890 is divisible by 6 (h) 4562 is divisible by 3(i) 40 090 is divisible by 5 (j) 123 456 is divisible by 9
3 Can $3407 be divided equally among
(a) two people (b) three people (c) nine people4 A stadium has 202 008 seats Can these be divided equally into
(a) 1047297ve blocks (b) six blocks (c) nine blocks
5 (a) I a number is divisible by 12 what other numbers must it be divisible by(b) I a number is divisible by 36 what other numbers must it be divisible by(c) How could you test i a number is divisible by 12 15 or 24
14 Powers and roots
Square numbers and square rootsA number is squared when it is multiplied by itsel For example the square o 5 is 5 times 5 = 25 Tsymbol or squared is 2 So 5 times 5 can also be written as 52
Te square root o a number is the number that was multiplied by itsel to get the squarenumber Te symbol or square root is You know that 25 = 52 so 25 = 5
Cube numbers and cube rootsA number is cubed when it is multiplied by itsel and then multiplied by itsel again For examplthe cube o 2 is 2 times 2 times 2 = 8 Te symbol or cubed is 3 So 2 times 2 times 2 can also be written as 23
Divisibility tests are notpart o the syllabus Tey
are just useul to knowwhen you work withactors and prime numbers
Tip
In section 11 you learned that the
product obtained when an integeris multiplied by itself is a square
number
REWIND
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
Te cube root o a number is the number that was multiplied by itsel to get the cube number
Te symbol or cube root is You know that 8 = 23 so = 2
2
2
a) Square numbers can be arranged to form a
square shape Tis is 22
2
2
2
b) Cube numbers can be arranged to form a sol
cube shape Tis is 23
Finding powers and roots
You can use your calculator to square or cube numbers quickly using the x 2 and x 3 key
or the x◻ key Use the or 3 keys to 1047297nd the roots I you donrsquot have a calculator yocan use the product o prime actors method to 1047297nd square and cube roots o numbers Both
methods are shown in the worked examples below
Worked example 8
Use your calculator to find
(a) 132 (b) 53 (c) 324 (d) 5123
(a) 132 = 169 Enter 1 3 x 2 =
(b) 53 = 125 Enter 5 x 3 = If you do not have a x 3 button then enter
5 x◻ 3 = for this key you have to enter the power
(c) 324 18Enter
3
2
4
=
(d) 512 83 Enter 3 5 1 2 =
Worked example 9
If you do not have a calculator you can write the integer as a product of primes and group the prime factors into pairs or
threes Look again at parts (c) and (d) of worked example 8
(c) 3 (d) 5123
(c)324 2 2
23 3
33 3
3times
2 times 3 times 3 = 18
324 18
Group the factors into pairs and write down the square root of each pair
Multiply the roots together to give you the square root of 324
(d)512 2 2
22 2
22 2
2
2 times 2 times 2 = 8
512 83
Group the factors into threes and write the cube root of each threesome
Multiply together to get the cube root of 512
Not all calculators have exactly the
same buttons x ◻ x y andand all mean the same thing on
different calculators
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number concepts
Unit 1 Number12
Exercise 111 1 Calculate
(a) 32 (b) 72 (c) 112 (d) 122 (e) 212
(f) 192 (g) 322 (h) 1002 (i) 142 (j) 682
2 Calculate
(a) 13 (b) 33 (c) 43 (d) 63 (e) 93
(f) 103 (g) 1003 (h) 183 (i) 303 (j) 2003
Learn the squares of all integersbetween 1 and 20 inclusiveYou will need to recognisethese quickly
3 Find a value o x to make each o these statements true
(a) x times x = 25 (b) x times x times x = 8 (c) x times x = 121(d) x times x times x = 729 (e) x times x = 324 (f) x times x = 400(g) x times x times x = 8000 (h) x times x = 225 (i) x times x times x = 1
(j) (k) 1 (l) = 1
(m) = (n) x 3 1= (o) 64 =
4 Use a calculator to 1047297nd the ollowing roots
(a) (b) 64 (c) 1 (d) (e) 1
(f) (g) 1 (h) 4 (i) 1296 (j) 1 64
(k)3
(l) 1 (m) 27 (n) 64 (o) 1000(p) 216 (q) 512 (r) 2 (s) 17283 (t) 5832
5 Use the product o prime actors given below to 1047297nd the square root o each numberShow your working
(a) 324 = 2 times 2 times 3 times 3 times 3 times 3 (b) 225 = 3 times 3 times 5 times 5(c) 784 = 2 times 2 times 2 times 2 times 7 times 7 (d) 2025 = 3 times 3 times 3 times 3 times 5 times 5(e) 19 600 = 2 times 2 times 2 times 2 times 5 times 5 times 7 times 7 (f) 250 000 = 2 times 2times 2 times 2times 5 times 5times 5 times 5times 5 times
6 Use the product o prime actors to 1047297nd the cube root o each number Show your working
(a) 27 = 3 times 3 times 3 (b) 729 = 3 times 3 times 3 times 3 times 3 times 3(c) 2197 = 13 times 13 times 13 (d) 1000 = 2 times 2 times 2 times 5 times 5 times 5
(e) 15 625=
5times
5times
5times
5times
5times
5(f) 32 768 = 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2 times 2
7 Calculate
(a) ( )2 (b) ( )2 (c) ( ) (d) ( )
(e) 16 (f) 16 (g) 6 64+ (h) 6 64
(i) 1 6minus (j) 1 36minus (k) 4times (l) 5 4times
(m) 4 (n) 4 (o) 36
4 (p)
36
8 Find the length o the edge o a cube with a volume o
(a) 1000 cm3 (b) 19 683 cm3 (c) 68 921 mm3 (d) 64 000 cm3
9 I the symbol means lsquoadd the square o the 1047297rst number to the cube o the secondnumberrsquo calculate
(a) 2 3 (b) 3 2 (c) 1 4 (d) 4 1 (e) 2 4(f) 4 2 (g) 1 9 (h) 9 1 (i) 5 2 (j) 2 5
Brackets act as grouping symbolsWork out any calculations insidebrackets before doing thecalculations outside the brackets
Root signs work in the same way
as a bracket If you have 25 9+ you must add 25 and 9 beforefinding the root
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
15 Working with directed numbers
A negative sign is used to indicate that values are less than zero For example on a thermometer on a ban
statement or in an elevator
When you use numbers to represent real-lie situations like temperatures altitude depth belosea level pro1047297t or loss and directions (on a grid) you sometimes need to use the negative sign
indicate the direction o the number For example a temperature o three degrees belowzero can be shown as minus3 degC Numbers like these which have direction are called directed
numbers So i a point 25 m above sea level is at +25 m then a point 25 m below sea level isat minus25 m
Exercise 112 1 Express each o these situations using a directed number
(a) a pro1047297t o $100 (b) 25 km below sea level(c) a drop o 10 marks (d) a gain o 2 kg(e) a loss o 15 kg (f) 8000 m above sea level(g) a temperature o 10 degC below zero (h) a all o 24 m(i) a debt o $2000 (j) an increase o $250(k) a time two hours behind GM (l) a height o 400 m(m) a bank balance o $45000
Comparing and ordering directed numbersIn mathematics directed numbers are also known as integers You can represent the set ointegers on a number line like this
ndash5 ndash9 ndash7 ndash8 ndash10 ndash3 ndash2 ndash1 0 1 2 3 4 5 6 7 8 9 10 ndash4 ndash6
Te further to the right a number is on the number line the greater its value
Exercise 113 1 Copy the numbers and 1047297ll in lt or gt to make a true statement
(a) (b) 4 (c) 1
(d) 6 4 (e) minus 4 (f) minus2 4(g) minus 1minus 1 (h) minus minus1 (i) minus
(j) minus (k) minus minus1 4 (l) minus minus
(m) (n) minus 11 (o) 1 minus
2 Arrange each set o numbers in ascending order
(a) minus8 7 10 minus1 minus12 (b) 4 minus3 minus4 minus10 9 minus8(c) minus11 minus5 minus7 7 0 minus12 (d) minus94 minus50 minus83 minus90 0
Once a direction is chosen to bepositive the opposite direction istaken to be negative So
bull if up is positive down is negative
bull if right is positive left is negative
bull if north is positive south isnegative
bull if above 0 is positive below 0 isnegative
You will use similar number lines
when solving linear inequalities in
chapter 14
FAST FORWARD
It is important that you understandhow to work with directed numbersearly in your IGCSE course Manytopics depend upon them
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number concepts
Unit 1 Number14
Living maths
3 Study the temperature graph careully
ndash4
ndash2
0
2
4
6
8
10
Sunday
14
Sunday
21
M T W T F S M T W T F S Sunday
28Day of the week
Temperature (degC)
(a) What was the temperature on Sunday 14 January
(b) By how much did the temperature drop rom Sunday 14 to Monday 15(c) What was the lowest temperature recorded(d) What is the difference between the highest and lowest temperatures(e) On Monday 29 January the temperature changed by minus12 degrees What was the
temperature on that day
4 Matt has a bank balance o $4550 He deposits $1500 and then withdraws $3200 What ishis new balance
5 Mr Singhrsquos bank account is $420 overdrawn
(a) Express this as a directed number(b) How much money will he need to deposit to get his account to have a balance o $500(c) He deposits $200 What will his new balance be
6 A diver 27 m below the surace o the water rises 16 m At what depth is she then
7 On a cold day in New York the temperature at 6 am was minus5 degC By noon the temperaturehad risen to 8 degC By 7 pm the temperature had dropped by 11 degC rom its value at noonWhat was the temperature at 7 pm
8 Local time in Abu Dhabi is our hours ahead o Greenwich Mean ime Local time inRio de Janeiro is three hours behind Greenwich Mean ime
(a) I it is 4 pm at Greenwich what time is it in Abu Dhabi(b) I it is 3 am in Greenwich what time is it in Rio de Janiero(c) I it is 3 pm in Rio de Janeiro what time is it in Abu Dhabi(d) I it is 8 am in Abu Dhabi what time is it in Rio de Janeiro
16 Order of operationsAt this level o mathematics you are expected to do more complicated calculations involvingmore than one operation (+ minus times and divide) When you are carrying out more complicatedcalculations you have to ollow a sequence o rules so that there is no conusion about whatoperations you should do 1047297rst Te rules governing the order o operations are
complete operations in grouping symbols 1047297rst (see page 15)bulldo division and multiplication next working rom lef to rightbulldo addition and subtractions last working rom lef to rightbull
The difference between the highestand lowest temperature is alsocalled the range of temperatures
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
Many people use the letters BODMAS to remember the order o operations Te letters stand o
Brackets
Of
D
ivide M
ultiply
dd S
ubtract
(Sometimes lsquoIrsquo or lsquoindicesrsquo is used instead o lsquoOrsquo or lsquoo rsquo)
BODMAS indicates that powers are considered afer brackets but beore all other operations
Grouping symbolsTe most common grouping symbols in mathematics are brackets Here are some examples othe different kinds o brackets used in mathematics
(4 + 9) times (10 divide 2)
[2(4 + 9) minus 4(3) minus 12]
2 minus [4(2 minus 7) minus 4(3 + 8)] minus 2 times 8
When you have more than one set o brackets in a calculation you work out the innermostset 1047297rst
Other symbols used to group operations are
raction bars egbull 5 12
root signs such as square roots and cube roots egbull 9 16
powers eg 5bull 2 or 43
Worked example 10Simplify
(a) 7 times (3 + 4) (b) (10 minus 4) times (4 + 9) (c) 45 minus [20 times (4 minus 3)]
(a) 7 times 7 = 49 (b) 6 times 13 = 78 (c) 45 minus [20 times 1] = 45 minus 20
= 25
Worked example 11
Calculate
(a)3+
8
2 (b)4 2817 9minus
(c)36 100 36divide + minus
(a) 3
6
67
=
)8times (b) ( )
8
4
= divide
(c) 36 100 36
64
8
11
divide + minus
=
=
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number concepts
Unit 1 Number16
Exercise 114 1 Calculate Show the steps in your working
(a) (4 + 7) times 3 (b) (20 minus 4) divide 4 (c) 50 divide (20 + 5) (d) 6 times (2 + 9)(e) (4 + 7) times 4 (f) (100 minus 40) times 3 (g) 16 + (25 divide 5) (h) 19 minus (12 + 2(i) 40 divide (12 minus 4) (j) 100 divide (4 + 16) (k) 121 divide (33 divide 3) (l) 15 times (15 minus 1
2 Calculate
(a) (4 + 8) times (16 minus 7) (b) (12 minus 4) times (6 + 3) (c) (9 + 4) minus (4 + 6)
(d) (33 + 17) divide (10 minus 5) (e) (4 times 2) + (8 times 3) (f) (9 times 7) divide (27 minus 20)(g) (105 minus 85) divide (16 divide 4) (h) (12 + 13) divide 52 (i) (56 minus 62) times (4 + 3)
3 Simpliy Remember to work rom the innermost grouping symbols to the outermost
(a) 4 + [12 minus (8 minus 5)] (b) 6 + [2 minus (2 times 0)](c) 8 + [60 minus (2 + 8)] (d) 200 minus [(4 + 12) minus (6 + 2)](e) 200100 minus [4 times (2 + 8)] (f) 6 + [5 times (2 + 30)] times 10(g) [(30 + 12) minus (7 + 9)] times 10 (h) 6 times [(20 divide 4) minus (6 minus 3) + 2](i) 1000 minus [6 times (4 + 20) minus 4 times (3 + 0)]
4 Calculate
(a) 6 + 72 (b) 29 minus 23 (c) 8 times 42
(d) 20minus
4divide
2 (e)
31 10
14 (f)
100 40
4
minus
(g) 1 36 (h) (i) 0 minus
5 Insert brackets into the ollowing calculations to make them true
(a) 3 times 4 + 6 = 30 (b) 25 minus 15 times 9 = 90 (c) 40 minus 10 times 3 = 90(d) 14 minus 9 times 2 = 10 (e) 12 + 3 divide 5 = 3 (f) 19 minus 9 times 15 = 150(g) 10 + 10 divide 6 minus 2 = 5 (h) 3 + 8 times 15 minus 9 = 66 (i) 9 minus 4 times 7 + 2 = 45(j) 10 minus 4 times 5 = 30 (k) 6 divide 3 + 3 times 5 = 5 (l) 15 minus 6 divide 2 = 12(m) 1 + 4 times 20 divide 5 = 20 (n) 8 + 5 minus 3 times 2 = 20 (o) 36 divide 3 times 3 minus 3 = 6(p) 3 times 4 minus 2 divide 6 = 1 (q) 40 divide 4 + 1 = 11 (r) 6 + 2 times 8 + 2 = 24
Working in the correct orderNow that you know what to do with grouping symbols you are going to apply the rules or ordo operations to perorm calculations with numbers
Exercise 115 1 Simpliy Show the steps in your working
(a) 5 times 10 + 3 (b) 5 times (10 + 3) (c) 2 + 10 times 3(d) (2 + 10) times 3 (e) 23 + 7 times 2 (f) 6 times 2 divide (3 + 3)
(g)15
2 5
minus (h) (17 + 1 ) divide 9 + 2 (i)
16
1
minus
(j) 17 + 3 times 21 (k) 48 minus (2 + 3) times 2 (l) 12 times 4 minus 4 times 8(m) 15 + 30 divide 3 + 6 (n) 20 minus 6 divide 3 + 3 (o) 10 minus 4 times 2 divide 2
2 Simpliy
(a) 18 minus 4 times 2 minus 3 (b) 14 minus (21 divide 3) (c) 24 divide 8 times (6 minus 5)(d) 42 divide 6 minus 3 minus 4 (e) 5 + 36 divide 6 minus 8 (f) (8 + 3) times (30 divide 3) divide 11
3 State whether the ollowing are true or alse
(a) (1 + 4) times 20 + 5 = 1 + (4 times 20) + 5 (b) 6 times (4 + 2) times 3 gt (6 times 4) divide 2 times 3(c) 8 + (5 minus 3) times 2 lt 8 + 5 minus (3 times 2) (d) 100 + 10 divide 10 gt (100 + 10) divide 10
A bracket lsquotypersquo is always twinnedwith another bracket of thesame typeshape This helpsmathematicians to understandthe order of calculations evenmore easily
You will apply the order of operationrules to fractions decimals and
algebraic expressions as you
progress through the course
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
copy Cambridge University Press 2012
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
4 Place the given numbers in the correct spaces to make a correct number sentence
(a) 0 2 5 10
(b) 9 11 13 18
(c) 1 3 8 14 16 =minus
(d) 4 5 6 9 12 ( (minus
Using your calculatorA calculator with algebraic logic will apply the rules or order o operations automatically Soyou enter 2 + 3 times 4 your calculator will do the multiplication 1047297rst and give you an answer o (Check that your calculator does this)
When the calculation contains brackets you must enter these to make sure your calculator dothe grouped sections 1047297rst
Experiment with your calculator bymaking several calculations withand without brackets For example3 times 2 + 6 and 3 times (2 + 6) Do youunderstand why these are different
Your calculator might only have one
type of bracket ( and )
If there are two different shapedbrackets in the calculation (such as[4 times (2 ndash 3)] enter the calculatorbracket symbol for each type
Worked example 12
Use a calculator to find
(a) 3 + 2 times 9 (b) (3 + 8) times 4 (c) (3 times 8 minus 4) minus (2 times 5 + 1)
(a) 21 Enter 3 + 2 times 9 =
(b) 44 Enter ( 3 + 8 ) times 4 =
(c) 9 Enter ( 3 times 8 minus 4 ) minus ( 2 times 5 + 1 ) =
Exercise 116 1 Use a calculator to 1047297nd the correct answer
(a) 10 minus 4 times 5 (b) 12 + 6 divide 7 minus 4(c) 3 + 4 times 5 minus 10 (d) 18 divide 3 times 5 minus 3 + 2
(e) 5 minus 3 times 8 minus 6 divide 2 (f) 7 + 3 divide 4 + 1(g) (1 + 4) times 20 divide 5 (h) 36 divide 6 times (3 minus 3)(i) (8 + 8) minus 6 times 2 (j) 100 minus 30 times (4 minus 3)(k) 24 divide (7 + 5) times 6 (l) [(60 minus 40) minus (53 minus 43)] times 2(m) [(12 + 6) divide 9] times 4 (n) [100 divide (4 + 16)] times 3(o) 4 times [25 divide (12 minus 7)]
2 Use your calculator to check whether the ollowing answers are correctI the answer is incorrect work out the correct answer
(a) 12 times 4 + 76 = 124 (b) 8 + 75 times 8 = 698(c) 12 times 18 minus 4 times 23 = 124 (d) (16 divide 4) times (7 + 3 times 4) = 76(e) (82 minus 36) times (2 + 6) = 16 (f) (3 times 7 minus 4) minus (4 + 6 divide 2) = 12
3 Each represents a missing operation Work out what it is
(a) 12 (28 24) = 3 (b) 84 10 8 = 4(c) 3 7(07 13) = 17 (d) 23 11 22 11 = 11(e) 40 5 (7 5) = 4 (f) 9 15 (3 2) = 12
4 Calculate
(a)16
1minus
(b) 4
1 1minus
(c) 1 5
2
times minus
In this section you will use yourcalculator to perform operationsin the correct order However youwill need to remember the orderof operations rules and apply themthroughout the book as you domore complicated examples usingyour calculator
Some calculators have two lsquominusrsquo
buttonsminus
and ( minus
) Thefirst means lsquosubtractrsquo and is used tosubtract one number from anotherThe second means lsquomake negativersquoExperiment with the buttons andmake sure that your calculator isdoing what you expect it to do
The more effectively you are able touse your calculator the faster andmore accurate your calculations arelikely to be If you have difficultywith this you will find advice andpractice exercises on the CD-ROM
copy Cambridge University Press 2012
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
copy Cambridge University Press 2012
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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1 Reviewing number concepts
Unit 1 Number18
(d)6 11
2 )17 4 (e)
1 (f)
6
4 5
+
(g)6 16
15 3
minus (h)
minus
5 8 3
+
minus
(divide 4
5 Use a calculator to 1047297nd the answer
(a)0 345
1
(b)
1
16 8 05
times
+
(c) 16 0 087
09
times (d)
19 087
4
6 Use your calculator to evaluate
(a) 64 125times (b) 62times
(c) (d) 41 minus
(e) (f) 145 minus3
(g) 1
4
1
4
1
4
1
4+
(h) 75 minus times1
17 Rounding numbersIn many calculations particularly with decimals you will not need to 1047297nd an exact answerInstead you will be asked to give an answer to a stated level o accuracy For exampleyou may be asked to give an answer correct to 2 decimal places or an answer correct to 3signi1047297cant 1047297gures
o round a number to a given decimal place you look at the value o the digit to the right o thespeci1047297ed place I it is 5 or greater you round up i it less than 5 you round down
Worked example 13
Round 64839906 to
(a) the nearest whole number (b) 1 decimal place (c) 3 decimal places
(a) 64839906 4 is in the units place
64839906 The next digit is 8 so you will round up to get 5
= 65 (to nearest whole number) To the nearest whole number
(b) 64839906 8 is in the first decimal place
64839906 The next digit is 3 so the 8 will remain unchanged
= 648 (1 dp) Correct to 1 decimal place
(c) 64839906 9 is in the third decimal place
64839906 The next digit is 9 so you need to round upWhen you round 9 up you get 10 so carry one to the previous digit and write 0 in
the place of the 9
= 64840 (3 dp) Correct to 3 decimal places
In this chapter you are only dealing
with square and cube numbers
and the roots of square and cube
numbers When you work with
indices and standard form in
chapter 5 you will need to apply
these skills and use your calculator
effectively to solve problems
involving any powers or roots
FAST FORWARD
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
o round to 3 signi1047297cant 1047297gures 1047297nd the third signi1047297cant digit and look at the value o thedigit to the right o it I it is 5 or greater add one to the third signi1047297cant digit and lose all o thother digits to the right I it is less than 5 leave the third signi1047297cant digit unchanged and loseall the other digits to the right as beore o round to a different number o signi1047297cant 1047297guresuse the same method but 1047297nd the appropriate signi1047297cant digit to start with the ourth or 4sthe seventh or 7s etc I you are rounding to a whole number write the appropriate number zeros afer the last signi1047297cant digit as place holders to keep the number the same size
Worked example 14
Round
(a) 1076 to 3 significant figures (b) 000736 to 1 significant figure
(a) 1076 The third significant figure is the 7 The next digit is 6 so round 7 up to get 8
= 108 (3sf) Correct to 3 significant figures
(b) 000736 The first significant figure is the 7 The next digit is 3 so 7 will not change
= 0007 (1sf) Correct to 1 significant figure
Exercise 117 1 Round each number to 2 decimal places
(a) 3185 (b) 0064 (c) 383456 (d) 2149 (e) 0999(f) 00456 (g) 0005 (h) 41567 (i) 8299 (j) 04236(k) 0062 (l) 0009 (m) 3016 (n) 120164 (o) 1511579
2 Express each number correct to
(i) 4 signi1047297cant 1047297gures (ii) 3 signi1047297cant 1047297gures (iii) 1 signi1047297cant 1047297gure
(a) 4512 (b) 12 305 (c) 65 238 (d) 32055(e) 25716 (f) 0000765 (g) 10087 (h) 734876(i) 000998 (j) 002814 (k) 310077 (l) 00064735
3 Change9
to a decimal using your calculator Express the answer correct to
(a) 3 decimal places (b) 2 decimal places (c) 1 decimal place(d) 3 signi1047297cant 1047297gures (e) 2 signi1047297cant 1047297gures (f) 1 signi1047297cant 1047297gure
The first significant digit of a numberis the first non-zero digit whenreading from left to right The nextdigit is the second significant digitthe next the third significant and soon All zeros after the first significantdigit are considered significant
Remember the first significantdigit in a number is the first non- zero digit reading from left toright Once you have read past thefirst non-zero digit all zeros thenbecome significant
You will use rounding to a given
number of decimal places andsignificant figures in almost all
of your work this year You will
also apply these skills to estimate
answers This is dealt with in more
detail in chapter 5
FAST FORWARD
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number concepts
Unit 1 Number20
SummaryDo you know the following
Numbers can be classi1047297ed as natural numbers integersbullprime numbers and square numbers
When you multiply an integer by itsel you get a squarebullnumber (x
2
) I you multiply it by itsel again you get acube number (x 3)
Te number you multiply to get a square is called thebullsquare root and the number you multiply to get a cubeis called the cube root Te symbol or square root is Te symbol or cube root is
A multiple is obtained by multiplying a number by abullnatural number Te LCM o two or more numbers isthe lowest multiple ound in all the sets o multiples
A actor o a number divides into it exactly Te HCF obulltwo or more numbers is the highest actor ound in allthe sets o actors
Prime numbers have only two actors 1 and the numberbull itsel Te number 1 is not a prime number
A prime actor is a number that is both a actor and abullprime number
All natural numbers that are not prime can be expressedbullas a product o prime actors
Integers are also called directed numbers Te sign obullan integer (minus or +) indicates whether its value is aboveor below 0
Mathematicians apply a standard set o rules to decidebullthe order in which operations must be carried outOperations in grouping symbols are worked out 1047297rst
then division and multiplication then addition andsubtraction
Are you able to
identiy natural numbers integers square numbers anbullprime numbers
1047297nd multiples and actors o numbers and identiy the
bull LCM and HCF
write numbers as products o their prime actors usingbulldivision and actor trees
calculate squares square roots cubes and cube roots obullnumbers
work with integers used in real-lie situationsbullapply the basic rules or operating with numbersbullperorm basic calculations using mental methods andbullwith a calculator
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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1 Reviewing number conce
Unit 1 Number
Examination practiceExam-style questions1 Here is a set o numbers minus4 minus1 0 3 4 6 9 15 16 19 20 Which o these numbers are
(a) natural numbers (b) square numbers (c) negative integers(d) prime numbers (e) multiples o two (f) actors o 80
2 (a) List all the actors o 12 (b) List all the actors o 24 (c) Find the HCF o 12 and 24
3 Find the HCF o 64 and 144
4 List the 1047297rst 1047297ve multiples o
(a) 12 (b) 18 (c) 30 (d) 80
5 Find the LCM o 24 and 36
6 List all the prime numbers rom 0 to 40
7 (a) Use a actor tree to express 400 as a product o prime actors(b) Use the division method to express 1080 as a product o prime actors(c) Use your answers to 1047297nd
(i) the LCM o 400 and 1080 (ii) the HCF o 400 and 1080
(iii) 4 (iv) whether 1080 is a cube number how can you tell
8 Calculate
(a) 262 (b) 433
9 What is the smallest number greater than 100 that is
(a) divisible by two (b) divisible by ten (c) divisible by our
10 At noon one day the outside temperature is 4 degC By midnight the temperature is 8 degrees lowerWhat temperature is it at midnight
11 Simpliy
(a) 6 times 2 + 4 times 5 (b) 4 times (100 minus 15) (c) (5 + 6) times 2 + (15 minus 3 times 2) minus 6
12 Add brackets to this statement to make it true
7 + 14 divide 4 minus 1 times 2 = 14
Past paper questions1 Insert brackets to make this statement correct
2 times 3 minus 4 + 5 = 3 [1]
[Question 2 Cambridge IGCSE Mathematics 0580 Paper 1 (Core) OctoberNovember 2006]
2 Calculate
(a)0548
1 6
(b)
0 0763
1
[2]
[Question 2a Cambridge IGCSE Mathematics 0580 Paper 1 (Core) MayJune 2009]
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httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3155Unit 2 Shape space and measures128
7 Perimeter areaand volumePerimeterbullAreabullIrrational numberbullSectorbullArcbullSemi-circlebullSolid
bull NetbullVerticesbullFacebullSurface areabullVolumebullApexbullSlant heightbull
Key words
Te glass pyramid at the entrance to the Louvre Art Gallery in Paris Reaching to a height of 206 m it is a
beautiful example of a three-dimensional object A smaller pyramid ndash suspended upside down ndash acts as a
skylight in an underground mall in front of the museum
When runners begin a race around a track they do not start in the same place because theirroutes are not the same length Being able to calculate the perimeters o the various lanes allowthe offi cials to stagger the start so that each runner covers the same distance
A can o paint will state how much area it should cover so being able to calculate the areas owalls and doors is very useul to make sure you buy the correct size can
How much water do you use when you take a bath instead o a shower As more households armetered or their water being able to work out the volume used will help to control the budget
In this chapter youwill learn how to
calculate areas andbull perimeters of two-dimensional shapes
calculate areas andbullperimeters of shapes thatcan be separated into twoor more simpler polygons
calculate areas andbullcircumferences of circles
calculate perimeters andbullareas of circular sectors
understand nets for three-bulldimensional solids
calculate volumes andbull surface areas of solids
calculate volumes andbullsurface area of pyramidscones and spheres
E X T E N D E D
E X T E N D E D
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7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 3255 1Unit 2 Shape space and measures
7 Perimeter area and volu
71 Perimeter and area in two dimensions
PolygonsA polygon is a 1047298at (two-dimensional) shape with three or more straight sides Te perimeter
a polygon is the sum o the lengths o its sides Te perimeter measures the total distance arouthe outside o the polygon
Te area o a polygon measures how much space is contained inside it
wo-dimensional shapes Formula for area
Quadrilaterals with parallel sides
b
h
b
h
b
h
rhombus rectangle parallelogram
Area = bh
riangles
b
h
b
h
b
h
Area =1
2 or
2
rapezium
b
h
b
h
a a
Area = 1
( ) or( )h
Here are some examples o other two-dimensional shapes
kite regular hexagon irregular pentagon
It is possible to 1047297nd areas oother polygons such as those othe lef by dividing the shapeinto triangles and quadrilatera
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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7 Perimeter area and volume
Unit 2 Shape space and measures130
At this point you may need to
remind yourself of the work you
did on transformation of formulae
in chapter 6
REWIND
Worked example 1
(a) Calculate the area of the shape shown in the diagram
5 cm
7 cm
6 cm
This shape can be divided into two simple polygons a rectangle and a triangle
Work out the area of each shape and then add them together
5 cm
7 cm
5 cm 6 cm
rectangle triangle
Area of rectangle = h = 2cm (substitute values in place of b and h )
Area of triangle = 1
2
1
25
1
215 2
h = times = times = cm
Total area = 35 + 15 = 50 cm2
(b) The area of a triangle is 40 cm2 If the base of the triangle is 5 cm find the height
A b htimes2
01
25
2
40 2
5
80
516
= times times
rArr times times
rArr =
h
h
cm
Use the formula for the area of a
triangle
Substitute all values that you know
Rearrange the formula to make h the
subject
The formula for the area of atriangle can be written in differentways
1
2 2
1
2
times =
=
htimes bh
b htimesOR
OR htimes2
Choose the way that works bestfor you but make sure you write itdown as part of your method
You do not usually have to redrawthe separate shapes but you mightfind it helpful
Units of areaI the dimensions o your shape are given in cm then the units o area are square centimetresand this is written cm2 For metres m2 is used and or kilometres km2 is used and so on Area ialways given in square units
TipYou should always giveunits or a 1047297nal answer i itis appropriate to do so Itcan however be conusingi you include units
throughout your working
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 71 1 By measuring the lengths o each side and adding them together 1047297nd the perimeter o eaco the ollowing shapes
(a) (b)
(c) (d)
2 Calculate the perimeter o each o the ollowing shapes
(a) 25 cm
55 cm
(b)
4 cm
3 cm
5 cm
(c) 7 cm
10 cm
4 cm4 cm
(d) 2 cm
2 cm
10 cm
9 cm
(e)
84 m
19 m
28 m25 m
72 m
(f)
9 km8 km
3 km3 km
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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7 Perimeter area and volume
Unit 2 Shape space and measures132
3 Calculate the area o each o the ollowing shapes
(a)
11 cm
5 cm
(b)
5 m
3 m
(c)
5 m
4 m
(d)
32 cm
14 cm
(e)
8 m
2 m
(f)
28 cm
(g) 6 cm
5 cm
10 cm
(h)
6 m
6 m
8 m
(i)
4 cm
4 cm
(j)
12 cm
6 cm
6 cm
4 Te ollowing shapes can all be divided into simpler shapes In each case 1047297nd the total area
(a)
5 m
8 m
4 m
8 m
(b)
72 m
45 m
12 m
21 m
51 m
Draw the simpler shapes separatelyand then calculate the individual
areas as in worked example 1
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 49 cm
53 cm
82 cm
(d)
78 cm
72 cm 734 cm
54 cm
21 cm
(e)
18 cm
24 cm
12 cm 12 cm
(f)
191 cm
382 cm
38 cm
(g)
371 cm
182 cm
784 cm
853 cm
5 For each o the ollowing shapes you are given the area and one other measurementFind the unknown length in each case
(a)
8 cm
h
242
cm
(b)
17 cm
b
289 2 cm
Write down the formula for the areain each case Substitute into theformula the values that you alreadyknow and then rearrange it to findthe unknown quantity
(c)
16 cm
a
14 cm132 2 cm
(d)
75 cm2
15 cm
b
(e) 6 cm
6 cm
18 cm
h
200 cm2
6 How many 20 cm by 30 cm rectangular tiles would you need to tile the outdoor area showbelow
17 m
48 m
09 m
26 m
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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7 Perimeter area and volume
Unit 2 Shape space and measures134
7 Sanjay has a square mirror measuring 10 cm by 10 cm Silvie has a square mirror whichcovers twice the area o Sanjayrsquos mirror Determine the dimensions o Silviersquos mirror correctto 2 decimal places
8 For each o the ollowing draw rough sketches and give the dimensions
(a) two rectangles with the same perimeter but different areas(b) two rectangles with the same area but different perimeters
(c) two parallelograms with the same perimeter but different areas(d) two parallelograms with the same area but different perimeters
Circles
Archimedes worked out the formula for the area of a circle
by inscribing and circumscribing polygons with increasing
numbers of sides
Te circle seems to appear everywhere in our everyday lives Whether driving a car running on arace track or playing basketball this is one o a number o shapes that are absolutely essential to u
c i r c u mf e
r e n c e
O is the
centre
r a d i u s
diameter
O
Finding the circumference of a circle
Circumerence is the word used to identiy the perimeter o a circle Note that the diameter = 2 times radius (2r ) Te Ancient Greeks knew that they could 1047297nd the circumerence o a circle by
multiplying the diameter by a particular number Tis number is now known as lsquoπ
rsquo (which is thGreek letter lsquoprsquo) pronounced lsquopirsquo (like apple pie) π is equal to 3141592654
Te circumerence o a circle can be ound using a number o ormulae that all mean the same thin
ircum erence iamete
==
ππr
lsquoInscribingrsquo here means to draw acircle inside a polygon so that it justtouches every edge lsquoCircumscribingrsquomeans to draw a circle outside apolygon that touches every vertex
π is an example of an irrational
number The properties of irrationalnumbers will be discussed later in
chapter 9
FAST FORWARD
(where d = diameter)
(where r = radius)
You learnt the names of the parts
of a circle in chapter 3 The diagram
on the right is a reminder of some
of the parts The diameter is the
line that passes through a circle and
splits it into two equal halves
REWIND
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Finding the area of a circle
Tere is a simple ormula or calculating the area o a circle Here is a method that shows howthe ormula can be worked out
Consider the circle shown in the diagram below It has been divided into 12 equal parts andthese have been rearranged to give the diagram on the right
length asymp times =1
22 r r
height asymp r r
π π
Because the parts o the circle are narrow the shape almost orms a rectangle with height equto the radius o the circle and the length equal to hal o the circumerence
Now the ormula or the area o a rectangle is Area = bh so
Area o a circle asymp times
=
1
2π
π
I you try this yoursel with a greater number o even narrower parts inside a circle you willnotice that the right-hand diagram will look even more like a rectangle
Tis indicates (but does not prove) that the area o a circle is given by A πr
You will now look at some examples so that you can see how to apply these ormulae
(Using the values o b and h shown above)
(Simpliy)
BODMAS in chapter 1 tells you to
calculate the square of the radius
before multiplying by π
REWIND
Note that in (a) the diameter isgiven and in (b) only the radiusis given Make sure that you lookcarefully at which measurement youare given
Worked example 2
For each of the following circles calculate the circumference and the area Give each
answer to 3 significant figures
(a)
O
8 mm
(a) diameter
mm
= times= times 8
25 1327
25 1
Area
mm
times
= times= times
r
r d
2
2
2
16
50 265
50 3
(b)
O
5 cm
(b) Circumference diameter
cm
= times
= times10
31 41531 4
( )
= times
Area = times
times
times
r 2
2
2
5
2578 539
78
TipYour calculator shouldhave a π button
I it does not use the
approximation 3142 butmake sure you write thisin your working Makesure you record the 1047297nalcalculator answer beorerounding and then statewhat level o accuracy yourounded to
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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7 Perimeter area and volume
Unit 2 Shape space and measures136
Worked example 3
Calculate the area of the shaded region in the diagram
25 cm
20 cm
18 cm
O
Shaded area = area of triangle ndash area of circle
Area
cm
minus
= times times minus times
1
2
12
18 2 5
160 365
160
2
2
2
r π
π
Substitute in values of b h and r
Round the answer In this
case it has been rounded to
3 significant figures
Exercise 72 1 Calculate the area and circumerence in each o the ollowing
(a)
O
4 m
(b)
O
31 mm
(c)
O
08 m
(d)
O1
2cm
(e)
O
2 km
(f)
O
2
mπ
In some cases you may find ithelpful to find a decimal value forthe radius and diameter beforegoing any further though you canenter exact values easily on mostmodern calculators If you knowhow to do so then this is a goodway to avoid the introduction ofrounding errors
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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7 Perimeter area and volu
1Unit 2 Shape space and measures
2 Calculate the area o the shaded region in each case
(a)
2 cm
18 cm
(b)
8 cm
8 cm
O
8 cm8 cm
(c)
12 m
7 m
2 m
1 m
O
O
(d)
5 cm
O
15 cm
10 cm
(e)
5 cm
O15 cm
12 cm
19 cm
(f)
3 cm
12 c
Living maths
3
pond
3 m10 m
12 m
Te diagram shows a plan or a rectangular garden with a circular pond Te part o thegarden not covered by the pond is to be covered by grass One bag o grass seed covers 1047297vsquare metres o lawn Calculate the number o bags o seed needed or the work to be do
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
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7 Perimeter area and volume
Unit 2 Shape space and measures138
4
04 m
05 m 12 m
Te diagram shows a road sign I the triangle is to be painted white and the rest o the signwill be painted red calculate the area covered by each colour
5 Sixteen identical circles are to be cut rom a square sheet o abric whose sides are 04 m lonFind the area o the lefover abric i the circles are made as large as possible
6 Anna and her riend usually order a large pizza to share Te large pizza has a diameter o24 cm Tis week they want to eat different things on their pizzas so they decide to order tw
small pizzas Te small pizza has a diameter o 12 cm Tey want to know i there is the samamount o pizza in two small pizzas as in one large Work out the answer
Arcs and sectors
major sector
O
minor
sector
r
r
θ
a r c l e n g t h
Te diagram shows a circle with two radii (plural oradius) drawn rom the centre
Te region contained in-between the two radii isknown as a sector Notice that there is a major sectoand a minor sector
A section o the circumerence is known as an arc
Te Greek letter θ represents the angle subtended at
the centre
Notice that the minor sector is a raction o the ull circle It isθ
6 o the circle
Area o a circle is πr 2 Te sector isθ
60 o a circle so replace lsquoorsquo with lsquotimesrsquo to give
Sector area =θ
6 times πr 2
Circumerence o a circle is 2π
r I the sector is
θ
6 o a circle then the length o the arc o a
sector isθ
36 o the circumerence So
Arc length =θ
360 times 2πr
Make sure that you remember the ollowing two special cases
Ibull θ = 90deg then you have a quarter o a circle Tis is known as a quadrant
Ibull θ = 180deg then you have a hal o a circle Tis is known as a semi-circle
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
copy Cambridge University Press 2012
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
copy Cambridge University Press 2012
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
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7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
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7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
Exercise 73 1 Find the area o the coloured region and 1047297nd the arc length l in each o the ollowing
(a)
70deg
l
O
18 cm
(b)
120deg 82 cm
l
O
(c)
64 cm95deg
O
l (d)
175deg
3 m
O
l
Note that for the perimeter you
need to add 5 cm twice Thishappens because you need toinclude the two straight edges
Note that the size of θ has notbeen given You need to calculate it
(θ = 360 minus 65)
Note that the base of the triangle is
the diameter of the circle
Worked example 4
Find the area and perimeter of shapes (a) and (b) and the area of shape (c)
Give your answer to 3 significant figures
(a)
30deg
O
5 m
Area
m
= times
times
θ
36030
3605
6 544
6 5
2
2
2
π
π
r Perimeter
m
= θ
3602
30360
2 5 5times
12 617
12 6
r +
(b)
O
4 cm65deg
Area
cm
=
minus360360 65
360295
36016
41 189
41 2
2
2
π
π
r
2
Perimeter
cm
=
+
θ
3602
295
3602 4 4times
28 594
28 6
r +
(c)
O
6 cm
4 cm
Total area = area of triangle + area of a semi-circle
Area
cm
= +
= times + times
1
2
1
21
2 times
1
249 132
49 1
2
2
2
r π
π
(Semi-circle is half of a circle
so divide circle area by 2)
You will be able to find the
perimeter of this third shape after
completing the work on Pythagorasrsquo
theorem in chapter 11
FAST FORWARD
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5055
7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4355
7 Perimeter area and volume
Unit 2 Shape space and measures140
2 For each o the ollowing shapes 1047297nd the area and perimeter
(a)
O
40deg 6 cm
(b)
O45deg
8 cm
(c) O
15deg32 cm
(d)
O
75deg5 m
(e)
O 172 cm
(f)
O
154 m
(g)
028 cm
O
(h)
43 cm
O
(i)
62deg
62deg
15 cm (j)
OO
6 m
14 m
O
3 For each o the ollowing 1047297nd the area and perimeter o the coloured region
(a)
5 cm
8 cm
(b)
9 cm
10 cm
6 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4655
7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4755
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4855
7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4955
7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5055
7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5255
7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4455
7 Perimeter area and volu
1Unit 2 Shape space and measures
(c) 30deg
30deg
5 m
12 m
(d)
84 cm
84 cm
(e)
18 m
4 Each o the ollowing shapes can be split into simpler shapesIn each case 1047297nd the perimeter and area
(a)
28 cm
(b)
100deg
32 c
(c)
15 cm
13 cm
(d)
3 cm
7 cm
11 cm
72 Three-dimensional objectsWe now move into three dimensions but will use many o the ormulae or two-dimensionalshapes in our calculations A three-dimensional object is called a solid
Nets of solidsA net is a two-dimensional shape that can be drawn cut out and olded to orm a three-dimensional solid
You might be asked tocount the number o
vertices (corners) edgesand aces that a solid has
Tip
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4555
7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4655
7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4755
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4855
7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4955
7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5055
7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4555
7 Perimeter area and volume
Unit 2 Shape space and measures142
Te ollowing shape is the net o a solid that you should be quite amiliar with
A
A
B
A
B
C
D
C
B D
I you old along the dotted lines and join the points with the same letters then you will ormthis cube
A C
B D
You should try this yoursel and look careully at which edges (sides) and which vertices (thepoints or corners) join up
Exercise 74 1 Te diagram shows a cuboid Draw a net or the cuboid
a
b
c
2 Te diagram shows the net o a solid
(a) Describe the solid in as much detail as you can(b) Which two points will join with point M when the net is
olded(c) Which edges are certainly equal in length to PQ
S T
M Z
R U Q V
N Y
P
O
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4755
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
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7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4955
7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5055
7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5255
7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4655
7 Perimeter area and volu
1Unit 2 Shape space and measures
3 A teacher asked her class to draw the net o a cuboid cereal box Tese are the diagrams ththree students drew Which o them is correct
4 How could you make a cardboard model o this octahedral dice Draw labelled sketches tshow your solution
73 Surface areas and volumes of solidsTe 1047298at two-dimensional suraces on the outside o a solid are called faces Te area o each can be ound using the techniques rom earlier in this chapter Te total area o the aces will us the surface area o the solid
Te volume is the amount o space contained inside the solid I the units given are cm then volume is measured in cubic centimetres (cm3) and so on
Some well known ormulae or surace area and volume are shown below
Cuboids
A cuboid has six rectangular aces 12 edges andeight vertices
I the length breadth and height o the cuboidare a b and c (respectively) then the surace areacan be ound by thinking about the areas o eachrectangular ace
a
b
c
Notice that the surace area is exactly the same asthe area o the cuboidrsquos net
Surace area o cuboid=
2(ab +
ac +
bc)Volume o cuboid = a times b times c
c
ac
c
c
b
b
a times b
(b) (c)(a)
It can be helpful to draw the netof a solid when trying to find itssurface area
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4755
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4855
7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4955
7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5055
7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5255
7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4755
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4855
7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4955
7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5055
7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5255
7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4855
7 Perimeter area and volu
1Unit 2 Shape space and measures
A cylinder can be lsquounwrappedrsquo to produce itsnet Te surace consists o two circular acesand a curved ace that can be 1047298attened to makea rectangle
Curved surace area o a cylinder = 2πrh
and
Volume = r h
2 r π
Exercise 75 1 Find the volume and surace area o the solid with the net shown in the diagram
3 cm
3 cm4 cm
5 cm
5 cm
11 cm
5 cm
5 cm
4 cm3 cm
3 cm
2 Find (i) the volume and (ii) the surace area o the cuboids with the ollowing dimensions
(a) length = 5 cm breadth = 8 cm height = 18 cm(b) length = 12 mm breadth = 24 mm height = 48 mm
Living maths
3 Te diagram shows a bottle crate Find the volume o the crate
FIZZ ZZ
90 cm
60 cm
80 cm
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4955
7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5055
7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5255
7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 4955
7 Perimeter area and volume
Unit 2 Shape space and measures146
4 Te diagram shows a pencil case in the shape o a triangular prism
8 cm
6 cm
10 cm
3 2 c m
Calculate(a) the volume and (b) the surace area o the pencil case
5 Te diagram shows a cylindrical drain Calculate the volume o the drain
12 m
3 m
6 Te diagram shows a tube containing chocolate sweets Calculate the total surace area o the tub
10 cm
22 cm
7 Te diagram shows the solid glass case or a clock Te case is a cuboid with a cylinderremoved (to 1047297t the clock mechanism) Calculate the volume o glass required to make theclock case
10 cm
8 cm
4 cm
5 cm
Donrsquot forget to include thecircular faces
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5055
7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5255
7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5055
7 Perimeter area and volu
1Unit 2 Shape space and measures
8 A storage company has a rectangular storage area 20 m long 8 m wide and 28 m high
(a) Find the volume o the storage area(b) How many cardboard boxes o dimensions 1 mtimes 05 m times 25 m can 1047297t into this storage ar(c) What is the surace area o each cardboard box
9 Vuyo is moving to Brazil or his new job He has hired a shipping container o dimensions3 m times 4 m times 4 m to move his belongings
(a) Calculate the volume o the container(b) He is provided with crates to 1047297t the dimensions o the container He needs to move eio these crates each with a volume o 5 m3 Will they 1047297t into one container
Pyramids
A pyramid is a solid with a polygon-shaped baseand triangular aces that meet at a point calledthe apex
I you 1047297nd the area o the base and the area oeach o the triangles then you can add these up to1047297nd the total surace area o the pyramid
Te volume can be ound by using the ollowingormula
Volume = 1
times ptimes erpendicular heigh
Cones
A cone is a special pyramid with a circular base Te length l is known as the slant height h is the perpendicular height
l
r
h
Te curved surace o the cone can be opened out and 1047298attenedto orm a sector o a circle
Curved surace area = πrl
and
Volume = 1
πr
The perpendicular height is theshortest distance from the base tothe apex
The slant height can be
calculated by using Pythagorasrsquo
theorem which you will meet
in chapter 11
FAST FORWARD
If you are asked for the totalsurface area of a cone you mustwork out the area of the circularbase and add it to the curvedsurface area
l
l e n g
t h
o f
a r c
o f
s e c t
o r
=
l e ng t h
of c i r c u m
f e r e n
c e o
f b
l
r
h
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5255
7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5155
7 Perimeter area and volume
Unit 2 Shape space and measures148
Spheres
Te diagram shows a sphere with radius r
Surace area = 2π
and
Volume= 4 πr
1 Te diagram shows a beach ball
(a) Find the surace area o the beach ball
(b) Find the volume o the beach ball
40 cm
2 Te diagram shows a metal ball bearing that iscompletely submerged in a cylinder o waterFind the volume o water in the cylinder
2 cm
15 cm
3 Te Great Pyramid at Giza has a square base o side 230 m and perpendicular height 146 m
Find the volume o the Pyramid
Exercise 76
r
The volume of the water is thevolume in the cylinder minus thedisplacement caused by the metalball The displacement is equal tothe volume of the metal ball
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5255
7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5255
7 Perimeter area and volu
1Unit 2 Shape space and measures
4 Te diagram shows a rocket that consistso a cone placed on top o a cylinder
(a) Find the surace area o the rocket
(b) Find the volume o the rocket
5 m 1 3
m
1 2 m
2 5
m
5 Te diagram shows a childrsquos toy thatconsists o a hemisphere (hal o a sphere)and a cone
(a) Find the volume o the toy(b) Find the surace area o the toy
8 cm
6 cm
10 cm
6 Te sphere and cone shown
in the diagram ha ve the same volume
Find the radius o the sphere
24 cm
83 cm
r
7 Te volume o the largersphere (o radius R) is twice the
volume o the smaller sphere(o radius r )
Find an equation connectingr to R
Rr
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5355
7 Perimeter area and volume
Unit 2 Shape space and measures150
8 A 32 cm long cardboard postage tube has a radius o 25 cm
(a) What is the volume o the tube(b) For posting the tube is sealed at both ends What is the surace area o the sealed tube
9 A hollow metal tube is made using a 5 mm metal sheet Te tube is 35 cm long and has anexterior diameter o 104 cm
(a) Draw a rough sketch o the tube and add its dimensions
(b) Write down all the calculations you will have to make to 1047297nd the volume o metal inthe tube(c) Calculate the volume o metal in the tube(d) How could you 1047297nd the total surace area o the outside plus the inside o the tube
SummaryDo you know the following
Te perimeter is the distance around the outside obulla two-dimensional shape and the area is the space
contained within the sidesCircumerence is the name or the perimeter o a circlebullI the units o length are given in cm then the units obullarea are cm2 and the units o volume are cm3 Tis is trueor any unit o length
A sector o a circle is the region contained in-betweenbulltwo radii o a circle Tis splits the circle into a minorsector and a major sector
An arc is a section o the circumerencebullPrisms pyramids spheres cubes and cuboids arebullexamples o three-dimensional objects (or solids)
A net is a two-dimensional shape that can be olded to
bull orm a solid
Te net o a solid can be useul when working out thebullsurace area o the solid
Are you able to
recognise different two-dimensional shapes and 1047297ndbulltheir areas
give the units o the areabullcalculate the areas o various two-dimensional shapesbulldivide a shape into simpler shapes and 1047297nd the areabull1047297nd unknown lengths when some lengths and an areabullare given
calculate the area and circumerence o a circlebullcalculate the perimeter arc length and area o a sectorbullrecognise nets o solidsbullold a net correctly to create its solidbull1047297nd the volumes and surace areas o a cuboid prismbulland cylinder
1047297nd the volumes o solids that can be broken intobullsimpler shapes
1047297nd the volumes and surace areas o a pyramid conebulland sphere
copy Cambridge University Press 2012
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5455
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]
8162019 Cambridge Igcse Mathematics Core and Extended Coursebook With CD Rom Cambridge Education Cambri Samples
httpslidepdfcomreaderfullcambridge-igcse-mathematics-core-and-extended-coursebook-with-cd-rom-cambridge 5555
7 Perimeter area and volume
3 120 m
d
A 400 metre running track has two straight sections each o length 120 metres and two semicircular ends(a) Calculate the total length o the curved sections o the track [1](b) Calculate d the distance between the parallel sections o the track [2]
[Question 18 Cambridge IGCSE Mathematics 0548 Paper 1 (Core) Nov 2005]
4 A large conerence table is made rom our rectangular sections and our corner sections Each rectangularsection is 4 m long and 12 m wide Each corner section is a quarter circle o radius 12 m
4
NOT TO
SCALE
Each person sitting at the conerence table requires one metre o its outside perimeter Calculate the greatestnumber o people who can sit around the outside o the table Show all your working [3]
[Question 11 Cambridge IGCSE Mathematics 0548 Paper 2 (Extended) Nov 2005]
5
A B12 cm
NOT TO
SCALE
Te largest possible circle is drawn inside a semi-circle as shown in the diagram Te distance AB is 12 centimetres(a) Find the shaded area [4](b) Find the perimeter o the shaded area [2]
[Question 23 Cambridge IGCSE Mathematics Paper 2 (Extended) June 2007]