Circuit - how much voltage is going through R3?

[STEMucator]

Homework Statement

A picture of the circuit : http://gyazo.com/54af2ebc610eb36ea345fe7ebdbedefa

Trying to find $R_3$.

Homework Equations

The Attempt at a Solution

I know the voltage across $R_1$ is $1.8V$.

That leaves $3V - 1.8V = 1.2V$ for the rest of the circuit. I know the voltage across $R_2$ is $1.2V$.

I know the current flowing through $R_3$ and $R_4$ is $0.06A$.

Now my question is how much voltage is going through $R_3$?

I know that $0.06A$ of current will flow through $R_3$ so I can use that with the voltage to find $R_3$.

 

[haruspex]

How does the voltage across R2 compare with that across R3+R4?