We consider a two-dimensional contact problem of indentation of an absolutely rigid cylinder into an inhomogeneous half space with periodic structure. The zone of periodicity consists of two homogeneous elastic layers. The solution of the classical problem of the theory of elasticity is compared with the solution of the problem in which the inhomogeneous half space is replaced by a homogenized space. We propose simple engineering formulas for the evaluation of contact characteristics (the width of the contact zone and the distribution of contact pressure) approximating the solution of the problem in the case where the homogenized medium inadequately models the inhomogeneous medium.