Exercise 62 Page 627

We are given that the measure of an interior angle of a regular n -gon is 108. The Polygon Interior Angles Sum Theorem tells us that the sum of the interior angle measures of an n-gon is (n-2)180. Since all angles in a regular polygon are congruent, our regular n-gon has n angles that each have a measure of 108. Therefore, the sum of the angle measures equals n times 108. (n-2)180 = 108n Let's solve this equation to find n. Knowing the value of n we will be able to identify the polygon.

Since the polygon has 5 sides, it is a pentagon.