We call a full circle or a full rotation 360 degrees. There's nothing magic or mathematical about that number. It was invented by people. It could have been any number they wanted.
But it was a great choice because it has a lot of factors. With 360 degrees in a full rotation, you can split up a full rotation into 2, 3, 4, 5, 6, 8, 9, 10, 12, 15, 18, 20, 24, 30, 36, 40, 45, 60, 72, 90, 120, or 180 equal pieces, without ever slicing up a degree !
