# Why is volume inversely proportional to pressure?

If temprature is directly proportional to volume (Charles's law) and temperature is directly proportional to pressure (Gay-Lussac's law), then why is pressure and volume are inversely proportional?

• By Boyale's law... – Zenix Dec 28 '19 at 16:48

$$\begin{cases} T \propto V\\ T \propto p \end{cases} \implies p \propto \frac 1 V$$