### Home > GC > Chapter 9 > Lesson 9.1.2 > Problem 9-21

9-21.

Review what you know about the angles of polygons below.

If the exterior angle of a polygon is

, what is the interior angle? What is the relationship between the interior and exterior angles of a polygon?

If the interior angle of a polygon is

, can it be a regular polygon? Why or why not? Refer to the Math Notes box in Lesson 8.1.4.

Find the sum of the interior angles of a regular

-gon. To calculate the sum of the interior angles of a polygon use

. .