Question

The formula to find the sum of the interior angles of a polygon

a- (n-4)*90°
b - (n-3)*180°
c- (2n-4)*180°
d- (2n-4)*90°​

Answer 1

A polygon with N sides has the sum of interior angles

(N-2) times 180°

Why does it work? Instead of the interior angles, consider the exterior angles (see Internal and external angles). The exterior angles are 180° minus the corresponding interior angles.