The Area of a Circle with Radius $r$ Is Given by the Function

Multiple Choice

The area of a circle with radius $r$ is given by the function $A(r) =\pi r^{2}$ . Find the area of the base of a circular storage tank if the radius is 5 feet long. Use $\pi \approx 3.14$ .

A) 15.7 square feet
B) 31.4 square feet
C) 78.5 square feet
D) 75 square feet