#### Answer

P=24$\sqrt 2$$\approx$33.9

#### Work Step by Step

An inscribed square has diameters 4 diagonals. The diagonals split the square into four 45 45 90 triangles. Therefore, a side of the square is equal to the radius times the square root of 2.
s=6$\sqrt 2$
P=4s
P=24$\sqrt 2$$\approx$33.9