Circle

Definition Circle is defined as the locus of a point moves in the plane such that it always has a certain distance (the radius) to a fixed point (the center).	Please enable Java for an interactive construction (with Cinderella).
	In the above figure, A is a fixed point in the plane; C is a movable point so that the length of AC is fixed. Move the point C to visualize the definition of the circle as a locus.