Difference between revisions of "Bretschneider's formula"
(creation) |
(No difference)
|
Revision as of 17:07, 21 June 2006
Let us have a quadrilateral with side lengths 
, and diagonals
. Bretschneider's formula says that
![$[ABCD]=\frac{1}{4}*\sqrt{4p^2q^2-(b^2+d^2-a^2-c^2)^2}$](http://latex.artofproblemsolving.com/7/5/9/7596249e635c730943d0f5493ab8e0d9f2399293.png)
.
It is derived through vector geometry.
