Homopolymer of methyl methacrylate (MMA) and its copolymer using different compositions of styrene and 1-decene were synthesized and characterized. The viscosity measurements of the synthesized homo polymer as well as the co polymer in the toluene solution at 313 K were performed. Different equations were used to calculate intrinsic viscosity, viscometric constants values and molecular weight of the synthesized polymers. The values of intrinsic viscosity and viscosity average molecular weight obtained by the two methods (single point determination and graphical extrapolation) were compared in order to verify the validity of the single point determination for the polymers. Viscometric properties derived included the determination of specific viscosity (it determines the contribution of solute to the viscosity of the solution), the reduced viscosity (that provides the measurements of the polymer capacity of increasing the solution viscosity) and intrinsic viscosity