Answer
$50$.
Work Step by Step
The given sides are
$a=14,b=48$
Use Pythagorean Theorem $c^2=a^2+b^2$ where $c$ is the length of the hypotenuse to obtain:
$c^2=(14)^2+(48)^2$
$c^2=196+2304$
$c^2=2500$
$c^2=50^2$
Take square root on both sides.
$c=50$
Hence, the hypotenuse is $50$.