Correct. Given $\displaystyle{V}=\frac{{1}}{{3}}{\left({30}\right)}{{s}}^{{2}}={10}{{s}}^{{2}}\usepackage{cmbright}\Huge\$ , you know that $\displaystyle{{s}}^{{2}}=\frac{{V}}{{10}}\usepackage{cmbright}\Huge\$ , so $\displaystyle{s}=\sqrt{{\frac{{V}}{{10}}}}\usepackage{cmbright}\Huge\$ .