For a Quadrilateral with sides of length , , , and , the Area is given by
(1) |
(2) |
(3) | |||
(4) |
(5) |
See also Bretschneider's Formula, Heron's Formula
References
Coxeter, H. S. M. and Greitzer, S. L. Geometry Revisited. Washington, DC: Math. Assoc. Amer., pp. 56-60,
1967.
Johnson, R. A. Modern Geometry: An Elementary Treatise on the Geometry of the Triangle and the Circle. Boston, MA:
Houghton Mifflin, pp. 81-82, 1929.