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

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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/