Given four points, 
, 
, 
, and 
, let 
be the orthocenter of 
.
Then 
is the orthocenter 
, 
is the orthocenter of 
,
and 
is the orthocenter of 
. The configuration 
is called an orthocentric quadrangle.
Orthocentric Quadrangle
See also
Orthocenter, Orthocentric Quadrilateral, Orthocentric SystemExplore with Wolfram|Alpha
References
Coxeter, H. S. M. and Greitzer, S. L. Geometry Revisited. Washington, DC: Math. Assoc. Amer., p. 39, 1967.Referenced on Wolfram|Alpha
Orthocentric QuadrangleCite this as:
Weisstein, Eric W. "Orthocentric Quadrangle." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/OrthocentricQuadrangle.html