## Stewart's Theorem

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.