find the length of the missing side.

Explanation:

Step1: Identify the theorem

Use the Pythagorean theorem $a^{2}+b^{2}=c^{2}$, where $a = 5$, $b = 12$, and $c$ is the hypotenuse.

Step2: Substitute values

$c^{2}=5^{2}+12^{2}=25 + 144=169$.

Step3: Solve for $c$

$c=\sqrt{169}=13$.

Answer:

13 cm