Reflectional Symmetry

1. Reflectional Symmetry Line Symmetry Internal and External

2. Reflection-Symmetric Figures A figure has symmetry if there is an isometry that maps the figure onto itself. If that isometry is a reflection, then the figure has reflection symmetry.

3. Lines of symmetry can cut through shapes that have reflection symmetry Draw in lines of symmetry for each: A C G none

4. Segment Theorem: Figures with reflection symmetry have their pre-images and images equal distances from the reflection mirror. 5 in 5 6 6 in 10 10 in

5. The reflection in this lake also has symmetry, but in this case: • the Line of Symmetry runs left-to-right • it is not perfect symmetry, because the image is changed a little by the lake surface.

8. Lines of Symmetry • How many lines of symmetry does the polygon have? 3

9. Lines of Symmetry • How many lines of symmetry does the shape have? 2

10. Lines of Symmetry • How many lines of symmetry does the shape have? 5

11. ABCDEFGHIJKLMNOPQR STUVWXYZ A H I M O T U V W X Y 1.  If the alphabet were printed in simple block printing, which capital letters would have vertical line symmetry? 2.  If the alphabet were printed in simple block printing, which capital letters would have horizontal line symmetry? B C D E H I K O X 3.  If the alphabet were printed in simple block printing, which capital letters would have BOTH vertical and horizontal symmetry? H I O X H I O X

12. 4.  Which of the following lettered items possesses line symmetry?  Consider vertical and/or horizontal symmetry. CircleALL that apply. a. the letter F b. an  equilateral triangle c. the letter X d. the word BOO e. a square f. the word WALLY g. the letter Q