1. The problem statement, all variables and given/known data http://imageshack.us/a/img210/3330/homeworkprob15.jpg [Broken] Find I0 in the network. (The middle resistor value was not given) 2. Relevant equations V = IR Voltage Division: (Voltage across series resistor) = [(resistance) / total series resistance)](total input V) Current Division (for 2 parallel resistors): (current across parallel resistor) = [(other resistor) / (sum of parallel resistors)](total incoming current)] Parallel resistors = (1/R1 + 1/R2)-1 Series Resistors = R1 + R2 Delta Y conversion and back for resistors 3. The attempt at a solution I really do not know where I should start. Other than all I can do being to simplify the 8 and 4 ohm resistors to 12 ohm. But then there's still that unknown resistor in the middle. I don't see how it would help to use y to T or the other way around to help.