times~{3}~=~540^\circ\) The number of triangles in each polygon is two less than the number of sides. The formula for calculating the sum of interior angles is: \(({n}~-~{2})~\times~180^\circ ...

Each polygon will always divide into two triangles fewer than the number of its sides. A hexagon will have four triangles. An octagon will have six triangles. So the sum of the interior angles of ...