We know ,
according to gases formula,
PV = nRT
where P is the pressure, V is the volume, n is the no of mole, R is gas constant and T is temperature.
now , R = PV/nT
dimension of pressure = [ML^-1T^-2]
dimension of volume = [ L^3 ]
dimension of mole = no dimension
dimension of temperature = [θ]
now , dimension of R =[ML^-1T^-2][L^3]/[K]
=[ ML²T⁻² θ⁻¹]