If you want to inscribe a polygon inside a circle, you have a formula that doesn't have to use the apothem. The formula is:
A = (nr²/2)sin(360/n)
Since the polygon is a hexagon, it has 6 sides. Thus, n = 6. Knowing the area, we can determine the radius of the circle, r.
166.28 = (6r²/2)sin(360/6)
r = 8 inches
Thus, the radius of the circle is 8 inches.