1. Transparency 6 Click the mouse button or press the Space Bar to display the answers.

2. Splash Screen

3. Example 6-3b Objective Identify symmetry and rotational symmetry

4. Example 6-3b Vocabulary Line symmetry Figures that match exactly when folded in half

5. Example 6-3b Vocabulary Line of symmetry A line that divides a figure into two halves that are reflections of each other

6. Example 6-3b Vocabulary Rotational symmetry A figure that can be turned less than 3600 about its center and still look like the original

7. Example 6-3b Vocabulary Angle of rotation The degree measure of the angle through which a figure is rotated

8. Lesson 6 Contents Example 1Identify Line Symmetry Example 2Identify Rotational Symmetry Example 3Identify Rotational Symmetry

9. Example 6-1a TRILOBITESThe trilobite is an animal that lived millions of year ago. Determine whether the figure has line symmetry. If it does, draw all lines of symmetry. If not, write none. When cut in half Left half is reflection of right side Answer: One vertical line of symmetry. 1/3

10. Example 6-1b BOTANY Determine whether the leaf has line symmetry. If it does, draw all lines of symmetry. If not, write none. Answer: One vertical line of symmetry. 1/3

11. Example 6-2a FLOWERS Determine whether the flower design has rotational symmetry. Write yes or no. If yes, name its angle(s) of rotation. 1 All petals look alike Count number of petals Rotational Symmetry involves a circle of 3600 2 4 Divide 360 by 4 (number of petals) 90 3 2/3

12. Example 6-2a Rotate 900 at a time to see the rotational symmetry 2/3

13. Example 6-2a Answer: Yes, has rotational symmetry. 90, 180, and 270 NOTE: Rotational symmetry will never rotate 3600 2/3

14. Example 6-2b FLOWERSDetermine whether the flower design has rotational symmetry. Write yes or no. If yes, name its angle(s) of rotation. Answer: yes, rotational symmetry; 180 2/3

15. Example 6-3a FLOWERSDetermine whether the flower design has rotational symmetry. Write yes or no. If yes, name its angle(s) of rotation. 1 All petals look alike 2 6 Count number of petals Rotational Symmetry involves a circle of 3600 Divide 360 by 6 (number of petals) 3 5 90 4 3/3

16. Example 6-3a Answer: Yes, has rotational symmetry. 60°, 120°, 180°, 240°, and 300°. 3/3

17. Example 6-3a NOTE: Rotational symmetry will never rotate 3600 Answer: Yes, this figure has rotational symmetry. It will match itself after being rotated60°, 120°, 180°, 240°, and 300°. 3/3

18. Example 6-3b * FLOWERSDetermine whether the flower design has rotational symmetry. Write yes or no. If yes, name its angle(s) of rotation. Answer: no rotational symmetry 3/3

19. End of Lesson 6 Assignment