Charles' Law relates the temperature (T measured in Kelvin) and volume (V) of a gas:
V T {\displaystyle {\frac {V}{T}}} = constant, or, V 1 T 1 {\displaystyle {\frac {V_{1}}{T_{1}}}} = V 2 T 2 {\displaystyle {\frac {V_{2}}{T_{2}}}} [1]