Given the Right Triangle shown in the picture, you can find the missing side length "x" by applying the Pythagorean Theorem. This states that:

Where "c" is the hypotenuse (the longest side), and "a" and "b" are the legs of the Right Triangle.
In this case, you can set up that:

Then, substituting values into the formula and solving for "x", you get:

![\begin{gathered} 64=x^2 \\ \sqrt[]{64}=x \\ x=8 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/high-school/jnvrc3xnvdnfd2uospga47obo16hd8vlly.png)
Hence, the answer is:
