59. The area, A, of a circle varies directly with the square of the radius, r. One of the following graphs shows the area, A, of a circle as the radius varies in the (r,A) coordinate plane. Which graph is it?

(Note: The (r,A) plane is the standard (x,y) coordinate plane with r along the horizontal axis and A along the vertical axis.)

Answer and Explanation

Your Answer is

Correct Answer is A

Explanation

Because A is proportional to the square of r, this function is a quadratic function with a parabola shape. Choose A.