Draw a Chordal (Power Line)

How to draw a Chordal, or Power Line of two circles.

Power of a Circle at a Point: [url]http://www.geogebratube.org/material/show/id/28302[/url] ________ For [i]100 Great Problems of Elementary Mathematics[/i], Heinrich Dorrie. [b]#31. Monge's Problem[/b] 1) Preliminary problem: find the locus of points with equal power at two circles (Chordal/Power Line): [url]http://www.geogebratube.org/material/show/id/33873[/url] *[b]2) Construction of a Power Line (tangent monster)[/b] 3) Solution of Monge's Problem: [url]http://www.geogebratube.org/material/show/id/33929[/url] 4) Vector Reduction: [url]http://www.geogebratube.org/material/show/id/33963[/url]