Solution:
Given:
From the above image,
Side length of 15 ft is the hypotenuse.
Side length of 6 ft is the leg.
To get the length of side x, we use the Pythagoras theorem.
[tex]\begin{gathered} \text{hypotenuse}^2=\text{opposite}^2+\text{adjacent}^2 \\ 15^2=6^2+x^2 \\ 225=36+x^2 \\ 225-36=x^2 \\ 189=x^2 \\ x=\sqrt[]{189} \\ x=13.75 \end{gathered}[/tex]
Therefore, the side length of x is 13.75
