What is the area of a circle with a diameter of 1 ft?

Area of a circle is defined as

A = pi x radius2

So if the diameter is 1 ft, the radius is 1/2 ft. I'll use pi=3.14. So the problem in feet is:

pi x (1/2)2 = 3.14 x 1/4 = .785 sq ft

In inches, radius = 6 inches so:

pi x 62 = 3.14 x 36 = 113.04 sq in