Angular distributions of the decay B(^{+}) → K*(892)(^{+}) μ(^{+}) μ(^{−}) are studied using events collected with the CMS detector in (\sqrt{s})=8TeV proton-proton collisions at the LHC, corresponding to an integrated luminosity of 20.0 fb⁻¹. The forward-backward asymmetry of the muons and the longitudinal polarization of the K*(892)(^{+}) meson are determined as a function of the square of the dimuon invariant mass. These are the first results from this exclusive decay mode and are in agreement with a standard model prediction.