The video above shows why the formula for the sum of the interior angles of a polygon with n sides is equal to . The polygon angle sum theorem shows the relationship between the number of sides of a polygon and the sum of its interior angles. The expression is the maximum number of triangles that can be formed in a polygon by drawing non-overlapping diagonals. The video above was labeled as a conjecture because the assumption is that it has not been proven that is indeed the number of triangles for all polygons with sides. If we make this assumption is true, then the conjecture in the video becomes a proof.