# Calculating thermal efficiency, I need HELP

## Homework Statement

You build a heat engine that takes 1.00 mol of an ideal diatomic gas through the cycle abc, where segment bc is isobaric and segment ca is isochoric. calculate the thermal efficiency of the engine.

this is a 5 part problem and I already solved for Wo and Wo=Qo I solved for Ta, Tb, and Tc. Ta=Tb. the problem gives me Va, Vb, Pa, and Pb in the figure.

## Homework Equations

e = W/Q$_{H}$ = 1 - |Q$_{C}$/Q$_{H}$|

W = |Q$_{H}$| - |Q$_{C}$|

## The Attempt at a Solution

I know that there are other ways to solve for e, but I don't know how to solve for e in this problem. I am completely lost. I cant use Carnot because thats for an ideal system, I cant use the one for the otto cycle because i dont have r and the problem doesnt tell me that it is otto cycle problem. WHAT DO I DO?