This page uses **JavaSketchpad**, a World-Wide-Web component of *The Geometer's Sketchpad.* Copyright © 1990-2001 by KCP Technologies, Inc. Licensed only for non-commercial use.

####

InvertCircle

Seventeen points on a circle are paired by segments to 17 points on another circle. In fact, each point is the inverse of its mate in the circle *(O,Z)*, and each of the two circles is the inverse of the other in the circle *(O,Z)*.
The point *X* determines the ratio |*AX*|/|*AB*|. This ratio is used to dilate the 17 points to a set of 17 intermediate points, which are linked by blue segments and reflected in segment *AB*. When *X* is animated, the linkage moves between the two circles, representing a "slow motion inversion" of one circle into the other.

Be sure to drag *C* and *D* so that pairs of circles overlap.

For more, see *GEOMETRY IN ACTION*, Chapter 3.