A regular heptagon or septagon is inscribed within a circle. The greatest distance d from the circumference to the perimeter is 12.31229 cm. Find the area A of the heptagon or septagon. A = _____ ...

A regular enneagon has nine equal sides and nine equal angles. The enneagon above is inscribed by an outer circle and it inscribes an inner circle. The difference in the areas of the outer and inner ...