View
223
Download
1
Category
Preview:
Citation preview
Math Grade 4Mrs. Ennis
Lines of SymmetryLesson 38
1. 897 + 8,954 + S = 9877
2. 18,052 – 399 = P
3. 83 x F = 415
4. 325 x Y = 6500
5. 146 ÷ 2 = H
6. 2 tons = _______ pounds
7. It is 2:15. What time was it 45 minutes ago?
8. 36,456 How many ten thousands?
9. Robbie has 3 bikes. He needs tires for all of them. Each tire costs $4.00. How much will he spend on tires?
10. Of the students in the 4th grade at Greensboro Day School, 46 play soccer, 23 play lacrosse and 32 are in the band. How many more students play a sport than are in the band?
Line Symmetry
• A shape has line symmetry when one half of it is the mirror image of the other half.
• Symmetry exists all around us.
Line Symmetry exists in nature but you may not
have noticed.
A line of symmetry is a line on which a figure can be folded so that both sides match.
Is a butterfly symmetrical?
To be symmetrical, the shape must have two halves that match exactly.The two halves are congruent.
Which of these flags have a line of symmetry?
England
United States of America
Which of these flags have a line of symmetry?
Which of these flags have a line of symmetry?
Canada
Which of these flags have a line of symmetry?
Maryland
At the beach there are a variety of shells with
line symmetry.
Animals that have Line Symmetry
Here are a few more great examples of mirror image in the animal kingdom.
This photograph shows 2 lines of symmetry. One vertical, the other along
the waterline.
(Notice how the prayer towers, called minarets, are reflected in the water and side to side).
an equilateral triangle has 3 internal angles and 3 lines of symmetry.
a square has 4 internal angles and 4
lines of symmetry.
a regular pentagon has 5 internal angles and 5 lines of symmetry.
a regular hexagon has 6 internal angles and 6 lines of symmetry .
How many lines of symmetry do these regular
polygons have?Do you see a pattern?
Drawing Lines of
Symmetry
Where are the lines of symmetry?
A B C D E FG H I J K L M N O P Q R S T U V W X Y Z
Infi
ni
te
Draw lines of symmetry for each letter with line symmetry.
Online Practice
Review Lesson- Symmetry
http://www.softschools.com/math/geometry/symmetry_game/
Virtual Symmetry
Math Fun:
A traffic light at one intersection changes every 28 seconds. The traffic light at the next intersection changes every 32 seconds.How long before they will both change together?
Answer:
They will both change together in 224 seconds or 3 minutes and 44 seconds.
http://mathlearnnc.sharpschool.com/UserFiles/Servers/Server_4507209/File/Instructional%20Resources/G4WW1-4.pdf
Resources:
www.adrianbruce.com/Symmetry/power/LineSymmetry.ppt
http://www.linkslearning.org/Kids/1_Math/2_Illustrated_Lessons/4_Line_Symmetry/http://www.softschools.com/math/geometry/symmetry_game/
http://www.techniquest.org/virtual/sketching/
Recommended