FrisbeeArchimedean Twin Circles

Archimedes proved that the two circles labeled "MAΘ" and "2007" on the  frisbee have the same size. This is always true no matter where we place the notch of the arbelos.
You can check this by dragging the red point in the construction below. The two green Twin Circles should always stay the same size.

Sorry, the GeoGebra Applet could not be started. Please make sure that Java 1.4.2 (or later) is installed and activated. (click here to install Java now)

Find out more about the twin circles:
  1. Radius of the Twin Circles - prove that they really have the same radius
  2. Constructing the Radius - construct the radius without a calculator
  3. Constructing the Twin Circles - construct the twin circles from scratch
Up: Contents Next: Radius of the Twin Circles