Answer
$P V^\gamma = \text{constant}$, $T V^{\gamma - 1} = \text{constant}$, and $P^{1-\gamma} T^\gamma = \text{constant}$, where $\gamma = \frac{C_p}{C_v}$.
Explanation
For a monoatomic ideal gas, $\gamma = \frac{5}{3} \approx 1.67$; for a diatomic gas, $\gamma = \frac{7}{5} = 1.40$.