To isolate $T_c$ (the cold temperature) from the efficiency formula:

$\% \text{Eff} = \left( 1 - \frac{T_c}{T_h} \right) \times 100\%$

Steps to isolate $T_c$:

1. Divide both sides by 100 to remove the percentage: $\frac{\% \text{Eff}}{100} = 1 - \frac{T_c}{T_h}$

2. Subtract 1 from both sides: $\frac{\% \text{Eff}}{100} - 1 = - \frac{T_c}{T_h}$

3. Multiply both sides by -1 to get rid of the negative sign: $1 - \frac{\% \text{Eff}}{100} = \frac{T_c}{T_h}$

4. Multiply both sides by $T_h$ to isolate $T_c$: $T_c = T_h \times \left( 1 - \frac{\% \text{Eff}}{100} \right)$

Thus, the isolated formula for $T_c$ is:

$T_c = T_h \times \left( 1 - \frac{\% \text{Eff}}{100} \right)$

Do you need any further clarification or details?

Here are 5 related questions to consider:

1. How does the efficiency of a heat engine depend on the temperature difference?
2. What would happen to the efficiency if $T_h$ and $T_c$ were very close?
3. How does an increase in $T_h$ affect the value of $T_c$?
4. Can the efficiency ever be 100% according to this formula?
5. How does this formula relate to Carnot's theorem?

Tip: Efficiency formulas often assume absolute temperature in Kelvin for accurate calculations, so ensure you use the right units!