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

3. Splash Screen

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

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

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

7. Example 6-3b Vocabulary Rotational symmetry A figure that can be turned less than 360 0 about its center and still look like the original

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

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

10. Example 6-1a TRILOBITES The 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. Answer: One vertical line of symmetry. When cut in half Left half is reflection of right side 1/3

11. 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

12. Example 6-2a FLOWERS Determine whether the flower design has rotational symmetry. Write yes or no. If yes, name its angle(s) of rotation. 2/3 All petals look alike Count number of petals 1 2 3 4 Rotational Symmetry involves a circle of 360 0 Divide 360 by 4 (number of petals) 90

13. Example 6-2a 2/3 Rotate 90 0 at a time to see the rotational symmetry

14. Example 6-2a Answer: Yes, has rotational symmetry. 90 , 180 , and 270  2/3 NOTE: Rotational symmetry will never rotate 360 0

15. Example 6-2b FLOWERS Determine 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

16. Example 6-3a FLOWERS Determine whether the flower design has rotational symmetry. Write yes or no. If yes, name its angle(s) of rotation. 3/3 All petals look alike Count number of petals 1 2 3 4 5 6 Rotational Symmetry involves a circle of 360 0 Divide 360 by 6 (number of petals) 90

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

18. Example 6-3a Answer: Yes, this figure has rotational symmetry. It will match itself after being rotated 60°, 120°, 180°, 240°, and 300°. 3/3 NOTE: Rotational symmetry will never rotate 360 0

19. Example 6-3b FLOWERS Determine 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

20. End of Lesson 6 Assignment Lesson 6:6Symmetry3 - 14 All