# parallelogram law

Let $ABCD$ be a parallelogram with side lengths $u,v$ and whose diagonals have lengths $d_{1}$ and $d_{2}$ then

 $2u^{2}+2v^{2}=d_{1}^{2}+d_{2}^{2}.$

 Title parallelogram law Canonical name ParallelogramLaw Date of creation 2013-03-22 12:02:23 Last modified on 2013-03-22 12:02:23 Owner drini (3) Last modified by drini (3) Numerical id 10 Author drini (3) Entry type Theorem Classification msc 51-00 Related topic Parallelogram Related topic Quadrilateral Related topic Rectangle Related topic Square Related topic Rhombus Related topic ApolloniusTheorem Related topic Median Related topic ParallelogramLaw2