  The electromagnetic form factors, charge radii and decay constants of pion, K
and K*(892) are calculated using the three forms of relativistic kinematics:
instant form, point form and (light) front form. Simple representations of the
mass operator together with single quark currents are employed with all the
forms. Making use of previously fixed parameters, together with the constituent
quark mass for the strange quark, a reasonable reproduction of the available
data for form factors, charge radii and decay constants of pion, rho, K and
K*(892) is obtained in front form. With instant form a similar description, but
with a systematic underestimation of the vector meson decay constants is
obtained using two different sets of parameters, one for pion and rho and
another one for K and K*(892). Point form produces a poor description of the
data.
