Circle Geometry
The radius of a circle:
The radius of a circle is the distance from the center of the circle to the outside edge.
The diameter of a circle:
The diameter of a circle is longest distance across a circle. (The diameter cuts through the center of the circle. This is what makes it the longest distance.)
The circumference of a circle:
The circumference of a circle is the perimeter -- the distance around the outer edge.Circumference =
where r = the radius of the circle
and pi = 3.141592...
where r = the radius of the circle
and pi = 3.141592...