Professor Pete Saheetar ate an entire pizza one night. Each time he took a bite, 9 square centimeters of pizza disappeared.
Prof. Saheetar was so hungry that once he started eating he could not stop. Twenty-eight minutes later
the pizza was finished. He took 20 seconds to lift the pizza to his mouth, take a bite, chew it, and
swallow it. He never paused until he was done.
To the nearest inch, what was the diameter of the pizza he ate?