Incorrect. Since $\displaystyle{V}={{s}}^{{2}}{h}\usepackage{cmbright}\Huge\$ , you know that $\displaystyle{4500}={{s}}^{{2}}{\left({20}\right)}\usepackage{cmbright}\Huge\$ . Solve for s by simplifying the equation to the form $\displaystyle{{s}}^{{2}}=\usepackage{cmbright}\Huge\$ something, then take the square root of both sides of the equation.