  We present a unified model describing electroweak properties of the pi and
rho mesons. Using a general method of relativistic parametrization of matrix
elements of local operators, adjusted for the nondiagonal in total angular
momentum case, we calculate the rho-meson lepton-decay constant f_rho using the
same parameters of free constituent quarks that have ensured exclusively good
results for the pi meson previously. The only free parameter, characterizing
quark interactions, which include additional spin-spin contribution and hence
differ from the $\pi$-meson case, is fixed by matching the decay constant to
its experimental value. The mean square charge radius is calculated,
<r^2_rho>=(0.56+-0.04) fm^2. This result verifies, for the rho-meson case, the
conjecture of equality between electromagnetic and strong radii of hadrons
tested previously for proton, pi and K mesons.
