1. Bellwork (on ½ sheet—turn in)
An angle of a triangle is 50. Find the measure of the angle formed by the angle bisectors of the other two angles.
If the measure of each interior angle of a regular polygon is find the number of sides of a polygon.

2. 7.4 Sum of the Exterior Angles
Students will be able to find the sum of the exterior angles of a polygon and one exterior angle of a regular polygon.

3. Exterior Angles (defn)
Name the exterior angle of this triangle?
What is true about the sum of an interior and exterior angle?
How many exterior angles are in a heptagon?

4. Discover
Together we will discover the formula for the sum of the exterior angles of a polygon.

5. Exterior Angle Summary (Toolbox!)
Se=360 E =

6. # of Diagonals Formula (Toolbox!)

7. Example 1 Find the sum of the exterior angles of a convex heptagon.
What is the measure of an exterior angle of an equiangular heptagon?

8. Example 2
If the measure of an exterior angle of a regular polygon is 15, how many sides does the polygon have?

9. Example 3
Find the measure of each interior and exterior angle of a dodecagon.

10. Example 4
What is the name of an equiangular polygon if the ratio of the measure of an interior angle to the measure of an exterior angle is 3:1?

11. Ticket to Leave
What is the measure of each interior and exterior angle of a regular 18-gon?

12. Homework
Pg. 309 # 3, 6, 8, 11b, 13, 14
Pg. 316 # 1, 3, 11-13
Quiz TOMORROW—Study All 5 Formulas!

13. Example 5
A polygon has 54 diagonals, how many sides does it have?

14. Extra Credit
In what polygon is the sum of the measures of the exterior angles, one per vertex, equal to the sum of the measures of the angles of the polygon?
Due Friday. Show all work for a full solution.

15. Extra Credit
In what polygon is the sum of the measures of the exterior angles, one per vertex, equal to the sum of the measures of the angles of the polygon?
Due Friday. Show all work for a full solution.

16. Extra Credit
In what polygon is the sum of the measures of the exterior angles, one per vertex, equal to the sum of the measures of the angles of the polygon?
Due Friday. Show all work for a full solution.

17. Extra Credit
In what polygon is the sum of the measures of the exterior angles, one per vertex, equal to the sum of the measures of the angles of the polygon?
Due Friday. Show all work for a full solution.

18. Extra Credit
In what polygon is the sum of the measures of the exterior angles, one per vertex, equal to the sum of the measures of the angles of the polygon?
Due Friday. Show all work for a full solution.

19. Extra Credit
In what polygon is the sum of the measures of the exterior angles, one per vertex, equal to the sum of the measures of the angles of the polygon?
Due Friday. Show all work for a full solution.

20. Extra Credit
In what polygon is the sum of the measures of the exterior angles, one per vertex, equal to the sum of the measures of the angles of the polygon?
Due Friday. Show all work for a full solution.