A basketball goal system is comprised of the rim and backboard. The National Basketball Association mandates that both meet precise measurements and placement relative to the court surface.
The backboard measures 72 inches wide and 42 inches in height and rests parallel to and 4 feet in from the baseline. A white inner square rests center directly above the rim measuring 24 inches wide and 18 inches tall. The free throw line rests exactly 15 feet from the plane of the backboard.
All rims measure exactly 18 inches in inside diameter. The rim is affixed to the backboard parallel to the floor and of equal distance from the vertical edges of either side of the board. The nearest point of the inside edge of the ring is 6 inches from the plane of the backboard face. The upper edge of the rim rests exactly 10 feet above the playing surface below.
The three-point arc is exactly 23 feet, 9 inches from the center of the hoop and 22 feet from the side parallel lines. A goal-tending violation occurs when a player from either team touches the ball when on or through the rim or within the imaginary cylinder above the rim.