The NBA's 3-point arc is 23 feet, 9 inches from the basket compared to the NCAA's 3-point arc of 20 feet, 9 inches from the basket:

http://www.macon.com/sports/college/university-of-georgia/bulldogs-beat/uga-football/article212727439.html

Crean revealed that he also put down a "4-point line" in the practice gym, which is an idea he borrowed from Philadelphia 76ers head coach Brett Brown. It's actually designed to help space the floor, especially when bigger players are on the court.