Question

What is the area of the inside surface of the ball to the nearest cm^2 ?

Answer 1

The inside radius of the ball is (half of 22 cm) less 0.5 cm, or 11 cm less 0.5 cm, or 10.5 cm.

The area of the inside surface of the ball is thus

A = 4*pi*r^2, which here is

A = 4*pi*(10.5 cm)^2 = 1385.4 cm^2.