Heron's Formula -- from Wolfram MathWorld
SEE ALSO: Brahmagupta's Formula, Bretschneider's Formula, Cayley-Menger Determinant, Heronian Tetrahedron, Heronian Triangle, Soddy Circles, SSS Theorem, Triangle REFERENCES: Bell, E. T. Men of Mathematics. New York: Simon and Schuster, p. 58 ......