Application of an in-plane magnetic field to rippled graphene will make the system be a plane with randomly distributed vector potentials. Massless Dirac fermions carrying charges on graphene are scattered by the vector potentials and magnetoresistance is induced proportional to the square of amplitude of in-plane magnetic field B2∥.Recently, Lundeberg and Folk proposed a formula showing dependence of the magnetoresistance on carrier density, in which the coefficient of B2∥ is given by a functional of the height-correlation function c(r) of ripples. In the present paper, we give exact and explicit expressions of the coefficient for the two cases such that c(r) is (i) exponential and (ii) Gaussian. The results are given using well-known special functions. Application of the present solutions in the vicinity of charge neutrality point should be careful because of the possible strong density inhomogeneity in rippled graphene. Here our analytic expressions are proposed, however, as trial interpolation formulas connecting the positive high-carrier-density regime and the negative one for magnetoresistance. Numerical fitting of our solutions to experimental data were performed. It is shown that the experimental data are well-described by the formula for the Gaussian heightcorrelation of ripples in the whole region of carrier density. The standard deviation Z of ripple height and the correlation length R of ripples are evaluated, which can be compared with direct experimental measurements.