1. Math 1 March 16 th What you need today in class: 1.Pick up a calculator 2.Turn in Homework – page 13 WARM-UP: You DO NOT have to copy the problem, but do show your work!! 1.Calculate the sum of the interior angles of a 15-gon. 2.Calculate the measure of one angle of a regular 18-gon.

3. Announcement for Freshman: You must pass your MATH class and your ENGLISH class to be promoted to 10 th grade. So, if you fail MATH OR ENGLISH, you will stay in 9 th grade next year.

4. If a convex polygon has n sides, then the sum of the measure of the interior angles is (n – 2)(180°)

5. Ex. 1 Use the regular pentagon to answer the questions. A)Find the sum of the measures of the interior angles. B)Find the measure of ONE interior angle 540° 108°

6. Two more important terms Exterior Angles Interior Angles

7. In any convex polygon, the sum of the measures of the exterior angles, one at each vertex, is 360°. 1 2 3 4 5

8. 1 3 2

9. If any convex polygon, the sum of the measures of the exterior angles, one at each vertex, is 360°. 1 3 2 4

10. Ex. 2 Find the measure of ONE exterior angle of a regular hexagon. 60 °

11. Ex. 3 Find the measure of ONE exterior angle of a regular heptagon. 51.4°

12. Go to page 14 Regular Polygon Interior Angle Sum Exterior Angle Sum Triangle Quadrilateral Pentagon Hexagon Heptagon Octagon Decagon Dodecagon N-gon

13. Assignment Page 18 –Questions 1-12 and 15-18

14. Ex. 4 Each exterior angle of a polygon is 18 . How many sides does it have? n = 20

15. Ex. 5 The sum of the measures of five interior angles of a hexagon is 535. What is the measure of the sixth angle? 185°

16. Ex. 6 The measure of the exterior angle of a quadrilateral are x, 3x, 5x, and 3x. Find the measure of each angle. 30°, 90°, 150°, and 90°

17. Ex. 7 If each interior angle of a regular polygon is 150 , then how many sides does the polygon have? n = 12

18. Foldable for Formulas