When you expand the equation in the bracket you'll find out that you'll get a^6 + 4a^4 + !6a^2 - 4a^4 - 16a^2 -64. then your final result will be a^6 - 64 <span />
The area of a regular octagon is: A = a * P / 2, where a is an apothem and P is a perimeter. P = 8 * 8 m = 64 m A = 9.7 m * 64 m / 2 A = 620.8 / 2 m² A = 310.4 m² Answer: The area of a regular octagon is 310.4 m².