View source for Fagnano problem

{{TEX|done}}{{MSC|51M04|51-03,01A50}}

The problem in which one is required to inscribe a triangle of least possible perimeter in a given acute-angled triangle. The solution is the [[orthocentric triangle]], that is, the triangle whose vertices are the feet of the altitudes of the given triangle. The problem was posed by G. Fagnano dei Toschi in 1775.

====References====
* H. S. M. Coxeter, S. L. Greitzer, "Geometry Revisited", Mathematical Association of America (1967) {{ISBN|0883856190}} {{ZBL|0166.16402}}