Look at the circuit shown in the figure above. With switch S, closed, you're making voltage measurements with your meter. Assume that each of the four resistors has a resistance value of 100 k ohm. You measure 3.6 V across resistor R₁, 1.2 V across resistor R2, 1.2 V across resistor Rs, and 2.4 V across resistor R4. What is the battery voltage in the circuit?