What the purpose of perpendicular lines in basketball?

Answer 1

The lines on a Basketball court assist with the rules. The half court line indicates where the game starts. The lines on the outside indicate the out-of-bounds lines. The "arc" near the basketball goal indicate the distance that extra points can be made. The small circle near the basketball goal indicates where free-throws happen and the lines that converge from the small circle towards the basket is called the key. During free-throws, players aren't allowed inside of the key. Additionally, during regular play, offensive players can't stay in the key for longer than 3 consecutive seconds.