what is the diameter of the basketball rim
Backboard (basketball) The top of the hoop is 10 feet (305 cm) above the ground. Regulation backboards are 72 inches (183 cm) wide by 42 inches (110 cm) tall. All basketball rims (hoops) are 18 inches (46 cm) in diameter. The inner rectangle on the backboard is 24 inches (61 cm) wide by 18 inches (46 cm) tall.[1]