Answer
The domain is the set of real numbers greater than or equal to $4$.
Work Step by Step
The given function is
$h(x)=\sqrt{x-4}$
The radicand cannot be negative.
So, $x-4$ is greater than or equal to zero.
$\Rightarrow x-4\geq 0$
Add $4$ to each side.
$\Rightarrow x\geq 4$
Hence, the domain is the set of real numbers greater than or equal to $4$.
