Densities and refractive indices at the temperature 298.15 K of {x(1)CH(3)COCH(3) + x(2)CH(3)OH + (1 - x(1) - x2)CH3CH(OH)CH3} and of the binaries : {xCH(3)COCH(3) + (1 - x)CH3CH(OH)CH3}, and {xCH(3)OH + (1 - x)CH3CH(OH)CH3} have been determined experimentally as a function of the mole fraction(s) at atmospheric pressure. Excess molar volumes and changes of refractive index on mixing were determined. Variable-degree polynomials have been fitted in order to compare the accuracy of different methods for the estimation of these results.