TOPICS
Search

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

 qw+rv:ru+pw:pv+qu.

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

Crossdifference, Crosspoint

Explore with Wolfram|Alpha

Cite this as:

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

Subject classifications