Answer
$5$
Work Step by Step
The triangle is right so the Pythagorean Theorem can be used to find the length of the hypotenuse.
Use the Pythagorean Theorem to solve for $c$ with $a=3$ and $b=4$ to obtain:
$a^2+b^2=c^2$
$3^2+4^2=c^2$
$9+16=c^2$
$25=c^2$
$c=5$
Thus, the hypotenuse of the right triangle is $5$ units.