I don't understand what the function of the start and stop parameters when programing a drawing for a circle on a canvas

Question

It has ctx. Begin path() ;
Ctx. Arc(x, y, r, start, stop) ;
Ctx. Stroke() ;

Why does it need start and stop when it already has the parameter for the radius

Please Any answer would be very very helpful

Answer 1

It's for the start and end angles. 0 is at 3 o'clock. It's useful to know in the case you want to draw 3/4s of a circle for instance.