Boyle's Law or Boyle-Mariotte's Law: Under constant temperature, the volume occupied by a given fixed mass of a gas is inversely proportional to its pressure.
Formula: [tex] \frac{ P_{1} }{ P_{2} } = \frac{ V_{2} }{ V_{1} } [/tex] Product of extremes equals product of means [tex] P_{1} * V_{1} = P_{2} * V_{2} [/tex]