State Boyle's Law and Charles's Law.

(N/A) Boyle's Law: For a fixed mass of an ideal gas at a constant temperature, the pressure $P$ is inversely proportional to its volume $V$. Mathematically, $P \propto 1/V$ or $PV = \text{constant}$.
Charles's Law: For a fixed mass of an ideal gas at a constant pressure, the volume $V$ is directly proportional to its absolute temperature $T$. Mathematically, $V \propto T$ or $V/T = \text{constant}$.