In other words, the area of the regular polygon equaled half the perimeter of the polygon times the radius of the inscribed circle. This is the example for an octagon. Compare 1985.0112.200 and ...

An exterior angle of a regular polygon can be found by dividing 360° by the number of sides (𝒏). Eg, for an eight-sided shape (octagon), divide 360° by 8 to find the size of an exterior angle ...