### Home > INT2 > Chapter 9 > Lesson 9.1.1 > Problem9-9

9-9.

How many sides does the regular polygon have if each interior angle has the following measure?

1. $60^\circ$

$60^\circ = \frac{180^\circ(n-2)}{n}$

$n = 3$ sides

1. $156^\circ$

1. $90^\circ$

1. $140^\circ$

$9$ sides

In addition, for regular polygons:

• The measure of each angle in a regular $n$-gon is $\frac{180^\circ(n-2)}{n}$ .

• The measure of each exterior angle in a regular $n$-gon is $\frac{360^\circ}{n}$ .