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Oldknow Points

The Perspective Centers of a triangle and the Tangential Triangles of its inner and outer Soddy Circles, given by

{\it Ol}=I+2{\it Ge}

{\it Ol'}=I-2{\it Ge},

where $I$ is the Incenter and Ge is the Gergonne Point.

See also Gergonne Point, Incenter, Perspective Center, Soddy Circles, Tangential Triangle


Oldknow, A. ``The Euler-Gergonne-Soddy Triangle of a Triangle.'' Amer. Math. Monthly 103, 319-329, 1996.

© 1996-9 Eric W. Weisstein