1. The problem statement, all variables and given/known data Four capacitors are connected as shown and connected to a battery to maintain a constant potential difference between points a and b. A charge Q2 = 61.6 μC is measured on capacitor 2. What is the charge on capacitor C3? 2. Relevant equations Q = CV; rules for combining capacitors (in parallel, add together; in series, take the inverse of the inverses added together) U = 1/2 C*V^2 = q^2/2C 3. The attempt at a solution The previous problems related to this one asked for the potential energy stored in the capacitor C2 and the capacitance of the entire network. I was able to figure those out easily, but with this problem I don't even know where to begin. I feel like without knowing the battery voltage, it's impossible to work backwards to find the voltage (and therefore the charge) over C3 and C4. I was thinking maybe trying to use some kind of modified voltage divider rule like I learned in one of my EE classes for resistor networks, and that looks something like this: C1,2/C2 = V2/V (I used the voltage divider rule for resistors in parallel since capacitors and resistors follow opposite rules) Solving for V (the voltage over the battery), I got 9.24 volts, but I still don't know how to use that to find the voltage over C3 and C4 (because I don't know how to find the voltage across C1) and frankly I don't feel like I'm approaching this problem in the right way anyway. I appreciate the help in advance!