The ideal gas law, states that PV = nRT;

where, P is pressure;

V is volume;

n is number of moles

R is gas constant

T is temperature

If there are two entities to be compared then, it can be compared as,

P1V1/T1 = P2V2/T2

as n and R can be considered as a constant.

Therefore, at constant pressure, the equation will get modified as;

V1/T1 = V2/T2