1.19(a) The critical constants of methane are $p_{\mathrm{c}}=45.6 \mathrm{~atm}, V_{\mathrm{c}}=98.7 \mathrm{~cm}^3 \mathrm{~mol}^{-1}$, and $T_{\mathrm{c}}=190.6 \mathrm{~K}$. Estimate the radius of the molecules.
0.118