1. Warm Up

2. Lesson 76, Symmetry Geometry

3. Vocabulary Symmetry: a property illustrated when the image of a transformation coincides with the preimage Line symmetry: image coincides with preimage after a reflection across a line Line of Symmetry: line that divides the figure into two congruent, reflected halves

4. Vocabulary

5. Example Identify whether each figure has a line of symmetry. If it does, draw the line of symmetry.

6. Example Triangle ABC has vertices A(0,0), B(2,0) and C(2,3). If the triangle is reflected over the x-axis, will the first triangle and the reflected triangle have a line of symmetry? If so, where is the line?

7. What is the order of rotational symmetry of the star? What is the angle of rotational symmetry?

8. Example Tiles often have many lines of symmetry so they can fit easily into patterns. How many lines of symmetry does each regular polygon with up to ten sides have?

9. Homework Questions

10. Correcting Homework Get your homework out so I can stamp it. If you do not have your homework complete, write your name on the board. Use red pen/pencil to correct. Trade with someone who has the homework done. If you didn’t get it done, you need to be working on finishing it now. Remember no cheating, and no work = no credit. Make sure you write CB with your name or you will lose your citizenship points for today.

11. Homework 1 st and 2 nd hour: Lesson 76: a-d, 2, 3, 5, 7, 9, 11, 14, 17, 19, 21, 22, 24, 26, 30 3 rd hour: Lesson 76: a-d, 2, 3, 5, 7, 9, 14, 17, 19, 21, 24, 30