Wheatstone bridge, prove converse.

[SrEstroncio]

Homework Statement

You are given a standard Wheatstone bridge, prove that the bridge is balanced if and only if $$R_x = R_3 \frac{R_2}{R_1}$$. Subindexes depend on the names assigned to each resistance. Proving that if the bridge is balanced THEN the resistors satisfy said relationship is easy, I am having prouble proving that IF $$R_x = R_3 \frac{R_2}{R_1}$$ then the bridge is balanced.

Homework Equations

The Attempt at a Solution

I have been trying to prove this using Kirchoff's laws around as many paths as i could find, but I am getting nowhere.

 

[lutzx135]

http://en.wikipedia.org/wiki/Wheatstone_bridge