Formula for area of a regular polygon inscribed in a circle
The area of a regular polygon is given by the formula below. area = (½) ( apothem ) ( perimeter) Several other area formulas are also available. Regular Polygon Formulas. n = number of sides. s = length of a side. r = apothem (radius of inscribed circle ) R = radius of circumcircle. Sum of interior angles = ( n - 2)·180°.