L = a √( 4 + 2√2) is the equation which can be used to calculate the length of each side of the octagon. In the equation i.e. L = a √( 4 + 2√2), in which ''a'' is the length of each side of the octagon. So by putting of ''a'' we get the length of each side of the octagon. The octagon is regular means all of its sides and angles are congruent or similar to each other. Each angle in the octagon has a measure of 135 degrees.
