Marissa has a wool rug that has the shape of a regular octagon in her living room. The diameter of the incircle of the rug measures 7 feet approximately. Which of the following is the approximate measure of one of the sides of wool rug?

A. 2.9 feet

B. 3.5 fest

C. 3.7 feet

D. 4.1 feet

Given the radius of the inscribed circle, the length of any side of the octagon (and any other polygon) is given by;

Side = 2r * tan (180/n) where r=radius and n=number of sides.

For octagon, n = 8 and radius is given by, r = 7/2 = 3.5 ft

Therefore,

Side = 2*3.5*tan (180/8) 2.8995 ft = 2.9 ft.

The correct answer is A.