Interior Angles of Regular Polygons Remember that the sum of the interior angles of a polygon is given by the formulaSum of interior angles = 180(n - 2) where n = the number of sides in the polygon.A polygon is called a REGULAR polygon when all of its sides are of the same length and all of its angles are of the same measure. A regular polygon is both equilateral … [Read more...] about Interior Angles of Regular Polygons