An NBA and official NCAA (college) court is 94 ft long and 50 ft wide.
A High School court is 84 ft long and 50 ft wide.
A Junior High court is 74 ft long and 42 ft wide.
Half court is well.. half the distance of the full court.. (I know, I didn't need to add that)
The free throw line is always 15 ft from the line to the backboard
The distance from the ground to the rim is 10 ft.
The 3 point arc in the NBA is 22ft to the center of the rim on the sides ( the arc starts 5 ft 3 in from the baseline, being a straight line until that point) then the curved part of the arc is 23ft. 9 in. from the center of the rim.
The 3 point arc in college and high school is 19 ft 9 in. (The straight part extends 63 in out from the baseline before the arc begins).
The key is 12 feet wide (the width of the free throw line) the backboard should extend 4 feet out over the baseline. The 12 ft wide free throw line forms the center of a circle with a 6 ft radius.
The backboard is 72 inches wide by 42 inches high and has an 18 inch diameter rim.
The inner square is marked above the rim in a rectangle of 24 inches wide and 18 inches high.
The line markings are white and 2 inches wide.
The picture below is worth a thousand words. It depicts the college and high school court dimensions.
College Court Measurements