1. ## rectangle law?

http://i33.tinypic.com/rqw8et.gif

i cant under why its call rectangle law?

2. Originally Posted by transgalactic
http://i33.tinypic.com/rqw8et.gif

i cant under why its call rectangle law?
In France it is called parallelogram law, because it states is that, in a parallelogram, the sum of the two squared lengths of the diagonals equals the sum of the four squared sidelengths.

(This parallelogram has vertices $0,f,f+g,g$)

3. mersi boku