Mrs. Ennis Lines of Symmetry Lesson 38 Math Grade 4 Mrs. Ennis Lines of Symmetry Lesson 38

897 + 8,954 + S = 9877 18,052 – 399 = P 83 x F = 415 325 x Y = 6500 146 ÷ 2 = H 2 tons = _______ pounds

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

Symmetry exists all around us. A shape has line symmetry when one half of it is the mirror image of the other half. Symmetry exists all around us.         How would you define the term 'line symmetry'?         Why might some people see line symmetry as a thing of beauty?

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. Line Symmetry exists in nature but you may not have noticed.

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

Which of these flags have a line of symmetry? No United States of America

Which of these flags have a line of symmetry? Canada

Which of these flags have a line of symmetry? No 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 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? + - - x

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 Draw lines of symmetry for each letter with line 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 Infinite

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.

Resources: http://mathlearnnc.sharpschool.com/UserFiles/Servers/Server_4507209/File/Instructional%20Resources/G4WW1-4.pdf 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/