Not sure what the mess above me says, but basically as long as you have an equation for the circle, you can plug the coordinates of your point into the x and y values of the equation and see if it equals out. If you don’t have an equation, you can just make one. Use (f-k)^2+(x-h)^2=r^2 where h and k are the coordinates of the center of the circle and r is the radius. Hope this helps!