How much is each angle of a 15-sided regular polygon? How much is each outer angle?

Given: number of side of polygon = 15

Measure of each exterior angle

⇒ ext. ∠ x

⇒ ext. ∠ x = 24°

The sum of inner and outer angle at vertex is 180°.

∠ x + ext. ∠ x = 180°

⇒ ∠ x + 24° = 180°

⇒ ∠ x = 180° - 24°

⇒ ∠ x = 156°

Measure of interior angles is 156° and exterior angle is 24°.