Upload
helena
View
45
Download
0
Tags:
Embed Size (px)
DESCRIPTION
Do Now #41 11/13/14. Jim wants to tile his shower wall. The wall is 7.5 feet tall and 4.5 feet wide. 1) What is the area of the wall? 2) If the tiles cost $1.50 per square foot, how much will it cost to tile the whole wall?. Homework Review/Dipstick Quiz. Chapter 3B Extension. - PowerPoint PPT Presentation
Citation preview
Jim wants to tile his shower wall. The wall is 7.5 feet tall and 4.5 feet wide. ◦ 1) What is the area of the wall?◦ 2) If the tiles cost $1.50 per square foot, how
much will it cost to tile the whole wall?
Do Now #41 11/13/14
Homework Review/Dipstick Quiz
Chapter 3B Extension
Parts of a Circle
Parts of a Circle
.Radius
Center
Circumference(outside)
Diameter
The distance across a circle passing through the centerA diameter cuts the circle exactly in
half
DIAMETER - Definition
The distance from the center of a circle to any point in the circumference
Plural Form: Radii2 Radii = 1 diameter
RADIUS - Definition
The center point of a circleCENTER - Definition
.
The distance around the circle
There are 2 formulas used to find the circumference of a circle
C = ∏d OR C =2∏r
CIRCUMFERENCE - Definition
∏ ≈ 3.14• Pi (∏) is pronounced like the word pie• ∏ is the 16th letter of the alphabet• ∏ is an irrational number (never ending and no digits repeat)
• ∏ can be expressed as a fraction• Math Holiday - PI DAY
Anyone Guess the Date???
∏ Facts
722
3.141592653589793238462643383279502884197169399375105820974944592307816406286208998628034825342117067…
Here are the 1st 100 digits of PI
You could find the circumference of a circle given EITHER the diameter OR the radius
Finding Circumference
Circumference FormulasGIVEN THE DIAMETER
C = ∏d
C = 3.14 x diameter
GIVEN THE RADIUS
C = 2∏r
C = 2 x 3.14 x radius OR
C = 6.28 x radius
Given Diamter Example 1
Given Diameter Example 2
When given the RADIUS of the circle you must use
C = 2∏r to find the circumference of the circle
because doubling the radius gives you the diameter.
Remember…
Given Radius Example 1
Given Radius Example 2
#1 Find the Circumference
You Try In Your Notebook…
You Try In Your Notebook…
6.2 in
#2 Find the Circumference
Master Pizza in Union offers large pizzas that have a diameter of 12 inches and medium pizzas that have a diameter of 8.5 inches. What is the difference in circumference between the two pizza sizes?
Word Problem #1 – Critical Thinking
The circular runners path in New York’s Central Park has a radius of 1.25 miles. What is the distance around the entire runners path?
If Lauren can jog one mile in 9 minutes, how long will it take her to jog the entire path?
Word Problem #2 – Critical Thinking