The domain of h(x) is [4,4.5).
Since f(x) has a domain of (4, 4.5) and g(x) has a domain of [4, 4.5), the domain of h(x) is the intersection of the domains of f(x) and g(x), which is [4, 4.5).
Note that the left endpoint 4 is included in the domain because it is included in the domain of g(x), even though it is not included in the domain of f(x).