### Home > MC2 > Chapter 6 > Lesson 6.1.6 > Problem6-63

6-63.

An NBA basketball hoop has an inside diameter of $18$ inches. The official NBA basketball has a maximum circumference of $30$ inches. What is the difference between the hoop diameter and the diameter of the ball? Show all of your work.

Circumference $= π ·$ diameter
If an official NBA basketball has a circumference of $30$ inches, what would its diameter be based on this formula?

Diameter $=\frac{30\text{ in}}{\pi}\approx9.55\text{ in}$
If $9.55$ inches is the approximate diameter of a ball, what is the difference between the hoop and the ball diameter?