Finding unknown values in a parallel-series circuit

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This is the given
Circuit schematic of Figure 10-11: voltage source Vs feeding two parallel branches, R1 (90V, 135W) in series with R3 (40Ω) on the left and R2 (90Ω) in series with R4 (1A, 60W) on the right. Below it, the questions list IR1, Vs, RT, IT and PT to calculate.


I need to find those unknowns but I have no idea where as to even start.
Any help would be appreciated, thanks a lot
 
Write down the Ohms's law, equations for calculating power P, and equations for adding resistors in series and parallel.
 
To start with you need to look at what is given in terms of your resistors.
For R1 you have PD and Power; and R4 you have Current and Power so use the formulas for power to find those resistances.
R1 and R3 are in series; R2 and R4 are also in series
To find the total resistance you will have to find the In Series Resistance first (Rs)and then you'll see that those subtotals will now be in Parallel to find the total Resistance Rt.
If you review PD and Current for Resistors in Series and Parallel it will help you find the It and Vs
 
Req=((R1+R3)*(R2+R4))/((R1+R3)+(R2+R4)); Req=Rt

Itot=Vs/Req;

Itot=I1+I2; I1-----arm 1 current,I2-----arm 2 current;

I1/I2=(R2+R4)/(R1+R3);

IR1=I1;

Pt=((Itot)^2)*(Req)