Current in parallel circuits

You could use the current divider rule. That would require you to find the total current in the circuit. Whats wrong with using V=IR?

 

Its used to find current when resistances are hooked up in parallel with each other. Here is a wiki picture that should clear things up for you:
http://upload.wikimedia.org/wikipedia/en/4/47/Cdr.GIF [Broken]

 

It changes a little when we have more than two resistances. Lets consider a circuit with three parallel branches. We know that the voltage drop across any resistor in a parallel circuit is equal to that of the source:

[tex] I_x = \frac{V_s}{R_x}[/tex]

[tex]V_s = I_TR_T[/tex] <--the source voltage is equal to the total current times the total resistance.

Now substituting [itex]I_TR_T[/itex] for V_s in the first equation (I_x).

[tex]I_x = \frac{I_TR_T}{R_x}[/tex]

We can therefore conclude that the current through any parallel resistor is in fact:
[tex]I_x = \frac{R_T}{R_x}\cdot I_T[/tex]

Hope it helps/