Crosssum

If P=p:q:r and U=u:v:w are distinct trilinear points, neither lying on a sideline of the reference triangle DeltaABC, then the crosssum of P and U is the point

It is the crosspoint of the isogonal conjugates of P and U. Therefore, U is the isogonal conjugate of the X-cross conjugate of the isogonal conjugate of P, and P is the isogonal conjugate of the X-cross conjugate of the isogonal conjugate of U.

See also

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Cite this as:

Weisstein, Eric W. "Crosssum." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/Crosssum.html

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