Let a Cevian be drawn on a Triangle
, and denote the lengths
and
, with . Then

This theorem is sometimes also called Apollonius' Theorem.

**References**

Altshiller-Court, N. ``Stewart's Theorem.'' §6B in
*College Geometry: A Second Course in Plane Geometry for Colleges and Normal Schools, 2nd ed., rev. enl.*
New York: Barnes and Noble, pp. 152-153, 1952.

Coxeter, H. S. M. and Greitzer, S. L. *Geometry Revisited.* Washington, DC: Math. Assoc. Amer., p. 6, 1967.

© 1996-9

1999-05-26