never was good at geometry help with this

r = 6, d = 12, a = \(9\pi\)

Circumference = Diameter x Pi

C = 12 x Pi - Feet

D = 12 Feet 

Radius = Diameter / 2

R = 12 / 2 = 6 Feet

Area =Radius^2 x Pi

Area =6^2 x 3.141592

Area =36Pi - Square feet, or ft^2.