Given a Triangle , the Triangle with Vertices at the feet of the Altitudes (perpendiculars from a point to the sides) is called the orthic triangle. The three lines are Concurrent at the Orthocenter of .

The centroid of the orthic triangle has Triangle Center Function

(Casey 1893, Kimberling 1994). The Orthocenter of the orthic triangle has Triangle Center Function

(Casey 1893, Kimberling 1994). The Symmedian Point of the orthic triangle has Triangle Center Function

(Casey 1893, Kimberling 1994).

**References**

Casey, J. *A Treatise on the Analytical Geometry of the Point, Line, Circle, and Conic Sections, Containing
an Account of Its Most Recent Extensions, with Numerous Examples, 2nd ed., rev. enl.* Dublin: Hodges, Figgis, & Co., p. 9, 1893.

Coxeter, H. S. M. and Greitzer, S. L. *Geometry Revisited.* Washington, DC: Math. Assoc. Amer., pp. 9 and 16-18,
1967.

Kimberling, C. ``Central Points and Central Lines in the Plane of a Triangle.'' *Math. Mag.* **67**, 163-187, 1994.

© 1996-9

1999-05-26