Pearson Geometry Common Core, 2011
PG
Pearson Geometry Common Core, 2011 View details
1. The Polygon Angle-Sum Theorems
Continue to next subchapter

Exercise 25 Page 356

The Polygon Angle-Sum Theorem says that the sum of the measures of the interior angles of an n -gon is (n-2)180.

18

Practice makes perfect

We are given that the sum of the interior angle measures of a polygon with n sides is 2880 and we want to find n. To do it, recall the Polygon Angle-Sum Theorem.

Polygon Angle-Sum Theorem

The sum of the measures of the interior angles of an n -gon is (n-2)180.

This theorem tells us that the sum of the measures of the interior angles of an n-gon is (n-2)180. We are given that the sum of the measures of the interior angles is 2880. (n-2)180= 2880 Let's solve the above equation to find n.
(n-2)180=2880
n-2=2880/180
n-2=16
n=18
We found that n=18. This means that the polygon with the given measures has 18 sides.

Extra

More About the Polygon Angle-Sum Theorem
The Polygon Interior Angles Theorem states that the sum of the measures of the interior angles of a polygon is given by the following formula. (n-2)* 180^(∘) In the formula, n is the number of sides the polygon has.
We can see that the sum of the interior angle measures of a polygon depends on the number of sides the polygon has. Therefore, we just need to know how many sides a polygon has in order to find the sum of the measures of its interior angles.