#### Answer

A=400$\pi$ ft$^2$$\approx$1257 ft$^2$
C=40$\pi$ ft$\approx$126 ft

#### Work Step by Step

r=$\frac{1}{2}$d
r=$\frac{1}{2}$(40)
r=20
A=$\pi$r$^2$
A=$\pi$(20)$^2$
A=400$\pi$ ft$^2$$\approx$1257 ft$^2$
C=$\pi$d
C=$\pi$40
C=40$\pi$ ft $\approx$126 ft