Rational Radius

In this picture, the radius of the large outer circle is 1, and the radius of the small inner circle is 0.3 = 3/10, which is rational.

This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com

Try adjusting the value of theta by moving the slider.

M Ondrus, August 14, 2012, Created with GeoGebra