So it becomes trival when you set your unit of measure to the radius = 1. Then divide the unit one in half until you line up two points.
You will then have a triangle the distance from your two points and the interior 90 degree angle. You can now use that triangle to plot any point on any circle.
To do this you will need a circle. That can be drawn with a compass. Remember math is a model so you can't abstract out the circle it must be a thing that you can model. Pi is not needed or used in any of the math here.
