From the given picture, we can see that the figure is a right triangle, so we can apply Pythagorean theorem, that is,

where x denotes the missing length. Then, our equation give us

By taking square root to both side, we have
![\begin{gathered} x=\sqrt[]{89} \\ x=9.4339 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/kxid925tjceutgkzfwen6q3b8v1t4po78t.png)
Therefore, by rounding this result to the nearest tenth, the answer is 9.4 ft