Answer:
![\boxed{\tt x=√(89) }](https://img.qammunity.org/2023/formulas/mathematics/high-school/c017ceyqpmbawn6cxqveyxf8l0pr63huri.png)
Explanation:
We'll use the Pythagorean Theorem
Equation:
![\tt a^2+b^2=c^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/pnnd95862lyv1yjsi2uoseelw0jjsmxngr.png)
where a and b are the lengths of the two legs of triangle, and c is the hypotenuse.
*A and b can be switched because they are legs*
![\tt a^2+b^2=c^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/pnnd95862lyv1yjsi2uoseelw0jjsmxngr.png)
Plug in the side lengths:
![\tt 5^2+8^2=x^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/mr3rvixprvylo656dv6xi6y2dtg9s2v7se.png)
Evaluate 5^2 and 8^2:
![\tt 25+64=x^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/wmrse0y5ufzwco3js3m98rgdg46mada5ws.png)
Add 25 and 64 = 89
![\tt 89=x^2](https://img.qammunity.org/2023/formulas/mathematics/high-school/lf8pyznrgr9kxyx91nvs7ex0ive1aw5kiq.png)
Now, take the square root of each side:
![\tt x=√(89)](https://img.qammunity.org/2023/formulas/mathematics/high-school/dxw0rh4kkiy58ag7eybkkxbv4k6c9wgh80.png)
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