David Little
Mathematics Department
Penn State University
Eberly College of Science
University Park, PA 16802
Office: 403 McAllister
Phone: (814) 865-3329
Fax: (814) 865-3735

Home Courses Math Links Resources Java Applets

Johnson's Theorem
Draw three circles of the same radius that share a common point. To do so, select three points on the circle below and use each point as the center of a circle that passes through the blue point.

Locate the three other points of intersection of the three circles you drew. Johnson's Theorem states that these points of intersection lie on a circle of the same radius as the original circles.