Answer:
162π - 324 (exact) or 184.938
Explanation:
You probably don't even need help on this one anymore, its just the same as the previous one I helped you with.
Diameter = a^2 + b^2 = c^2 = 18^2 + 18^2 = c^2
√648 = c (this is exact) so radius is √648/2
Area of square = lw = 324
Area of circle = (√648/2)^2π = (648/4)π = 162π
Area of shaded region = 162π - 324 (exact) or 184.938