In order to solve this problem, use the following equations and steps shown: \begin{align} &\cssId{Step1}{L^2 = x^2 + h^2}\\[3px] &\cssId{Step2}{h^2 = L^2 - x^2}\\[3px] &\cssId{Step3}{h = \sqrt{L^2 - x^2}}\\[3px] \end{align}