Question

find the length of the third side. if necessary, round to the nearest tenth.

Explanation:

Step1: Apply Pythagorean theorem

Let the unknown side be $x$. In a right - triangle, the Pythagorean theorem is $a^{2}+b^{2}=c^{2}$, where $c$ is the hypotenuse. Here, if the hypotenuse $c = 5$ and one side $a = 4$, then $x^{2}+4^{2}=5^{2}$.

Step2: Solve for $x$

$x^{2}=5^{2}-4^{2}$. So $x^{2}=25 - 16=9$. Then $x=\sqrt{9}=3$.

Answer:

3