Find the size of each interior angle of a regular polygon of 15 sides.

156°

Explanation:

Each triangle has an angle sum of 180 degrees.

The sum of the interior angles of the 15 sided polygon =

(n-2) 180°

(n-2) 180°

(15-2) * 180°

13 * 180 = 2340 °

Since the 15 sided polygon is regular, this total is shared equally among the 15 interior angles. Each interior angle must have a measure of

2340° : 15 = 156 °each