Woo circles

In geometry, the Woo circles, introduced by Peter Y. Woo, are a set of infinitely many Archimedean circles.

Two of infinitely many Woo circles (green) all have the center on the Schoch line (cyan)

Construction

Form an arbelos with the two inner semicircles tangent at point C. Let m denote any nonnegative real number. Draw two circles, with radii m times the radii of the smaller two arbelos semicircles, centered on the arbelos ground line, also tangent to each other at point C and with radius m times the radius of the corresponding small arbelos arc. Any circle centered on the Schoch line and externally tangent to the circles is a Woo circle.^[1]

See also

• Schoch circles