1. Math 1 March 19 th What you need today in class: 1.Pick up a calculator and warm-up sheet 2.Turn in Homework – page 18 WARM-UP (Don’t copy question – just show work and give answer) 1.Find the measure of ONE exterior angle of a regular octagon. 2.Find the measure of ONE interior angle of a 11-gon.

2. CHECK HOMEWORK – FRONT 1. CONVEX POLYGON 2. CONCAVE POLYGON 3. NOT A POLYGON 4. QUADRILATERAL PENTAGON HEXAGON OCTAGON DECAGON N-GON 5. 180(n – 2) 6. 360 O 7. 360°/360° 8. 720 o /360 o 9. 1440°/360° 10. 540 o /360 o 11. 1080°/360° 12. 2880 o /360 o 15. REGULAR 16. 60 o /120 o 17. 120°/60° 18. 144 o /36 o

3. Summary Notes on Page 12 Interior Angle SUM ONE Interior Angle Exterior Angle SUM ONE Exterior Angle

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

5. 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°

6. 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°

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

8. Notes: p. 16 A.INTERIOR ANGLES 1. How do you find the sum of ALL of the INTERIOR ANGLES of a polygon?

9. A.INTERIOR ANGLES 1. How do you find the sum of ALL of the INTERIOR ANGLES of a polygon? 2. How do you find the measure of ONE INTERIOR ANGLE of a REGULAR polygon?

10. A.INTERIOR ANGLES 1. How do you find the sum of ALL of the INTERIOR ANGLES of a polygon? 2. How do you find the measure of ONE INTERIOR ANGLE of a REGULAR polygon? 3. How do you find the measure of ONE INTERIOR ANGLE of a non-regular polygon?

11. B.EXTERIOR ANGLES 1. The sum of the measures of ALL the EXTERIOR ANGLES of a polygon is always ______.

12. B.EXTERIOR ANGLES 1. The sum of the measures of ALL the EXTERIOR ANGLES of a polygon is always ______. 2. How do you find the measure of ONE EXTERIOR ANGLE of a REGULAR polygon?

13. C.FINDING AN INTERIOR & EXTERIOR ANGLE AT THE SAME TIME An interior angle and an exterior angle form a __________ ____________.

14. C.FINDING AN INTERIOR & EXTERIOR ANGLE AT THE SAME TIME An interior angle and an exterior angle form a __________ ____________. 1 st : Find the EXTERIOR ANGLE 2 nd : Find the INTERIOR ANGLE using the linear pair relationship. a) Find the interior and exterior angle of a regular hexagon.

15. HOMEWORK PAGE 19