Select the number of sides/vertices of a regular polygon. The polygon is shown inscribed in a circle of radius 1. The side length, apothem, perimeter, area, and radius of circle (always 1) are shown. The perimeter of the regular polygon approaches 2 pi as the number of sides goes to infinity (up to 20 sides may be selected). The area of the regular polygon approaches pi as the number of sides goes to infinity.