Sum of Interior Angles The interior angles of any polygon always add up to a constant value, which depends only on the number of sides. For example the interior angles of a pentagon always add up to 540° no matter if it regular or irregular, convex or concave, or what size and shape it is. The sum of the interior angles of a polygon is given by the formula: sum = 180 ( n − 2 )
Sample response: Any polygon can be broken into triangles. There are two less triangles than the number of sides in the polygon. You can multiply the number of triangles formed by 180° to find the sum of the interior angles. The sum can be written as (n – 2)180, where n is the number of sides.
