The utility of the ferromagnetic-resonance (FMR) technique to determine accurately the spontaneous magnetization and initial susceptibility critical exponents \ensuremath{\beta} and \ensuremath{\gamma}, which characterize the ferromagnetic (FM) -paramagnetic (PM) phase transition at the Curie temperature ${\mathit{T}}_{\mathit{C}}$ for ferromagnetic materials is demonstrated through a detailed comparative study on amorphous ${\mathrm{Fe}}_{90}$${\mathrm{Zr}}_{10}$ alloy, which involves bulk magnetization and FMR measurements performed on the same sample in the critical region. Magnetization data deduced from the FMR measurements taken on amorphous ${\mathrm{Fe}}_{90\mathrm{\ensuremath{-}}\mathit{x}}$${\mathrm{Co}}_{\mathit{x}}$${\mathrm{Zr}}_{10}$ alloys with x=0, 1, 2, 4, 6, and 8 in the critical region satisfy the magnetic equation of state characteristic of a second-order phase transition. Contrary to the anomalously large values of the exponents \ensuremath{\beta} and \ensuremath{\gamma} reported earlier, the present values, \ensuremath{\beta}=0.38\ifmmode\pm\else\textpm\fi{}0.03 and \ensuremath{\gamma}=1.38\ifmmode\pm\else\textpm\fi{}0.06, are composition-independent and match very well the three-dimensional Heisenberg values. The fraction of spins that actually participates in the FM-PM phase transition, c, is found to increase with the Co concentration as c(x)-c(0)\ensuremath{\simeq}${\mathit{ax}}^{2}$ and possess a small value of 11% for the alloy with x=0. The ``peak-to-peak'' FMR linewidth (\ensuremath{\Delta}${\mathit{H}}_{\mathrm{pp}}$) varies with temperature in accordance with the empirical relation \ensuremath{\Delta}${\mathit{H}}_{\mathrm{pp}}$(T)=\ensuremath{\Delta}H(0)+[A/${\mathit{M}}_{\mathit{s}}$(T)], where ${\mathit{M}}_{\mathit{s}}$ is the saturation magnetization. Both the Land\'e splitting factor g as well as the Gilbert damping parameter \ensuremath{\lambda} are independent of temperature, but, with increasing Co concentration (x), \ensuremath{\lambda} decreases slowly while g stays constant at a value 2.07\ifmmode\pm\else\textpm\fi{}0.02.