Question about a Wheatstone bridge
As Dampmaskin said, the schematic and values you have posted do not make a balanced bridge. So that makes it difficult to evaluate the circuit based on the premise of a "balanced state" of the question. 

However, the only voltage source in the system, is V1 at 5V. We certainly can see how much power a resistor would consume in a worst-case condition of being placed directly across V1. Testing the smallest resistors, R1 and R2:

\$P=\dfrac{E^2}{R}  =\dfrac{5V^2}{100\Omega}=250mW\$

So balanced or not, you can't really exceed the maximum power ratings.