We know that the triangle has an area of 53 sq in.
We also know that the area of any triangle is:
[tex]A=\frac{1}{2}b\cdot h[/tex]In this case, the base and the height are equal to x. Then:
[tex]A=\frac{1}{2}x\cdot x=\frac{1}{2}x^2[/tex]And, as we said, the area is 53, this means that:
[tex]\frac{1}{2}x^2=53[/tex]Solving for x, we have:
[tex]\begin{gathered} \frac{1}{2}x^2=53 \\ x^2=2\cdot53 \\ x^2=106 \\ x=\sqrt[]{106} \\ x=10.3 \end{gathered}[/tex]Therefore, x=10.3.