The formula for calculating the size of an interior angle is: interior angle of a polygon = sum of interior angles ÷ number of sides. The sum of exterior angles of a polygon is 360°. The formula ...
The sum of the interior angles is: \({180}~\times~{3}~=~540^\circ\) The number of triangles in each polygon is two less than the number of sides. The formula ... polygon is the exterior angle.