To use the quotient rule for exponents, we know that:
\[ \frac{a^m}{a^n} = a^{m-n} \]
Given the equation:
\[ \frac{h^{450}}{h^{?}} = h^{250} \]
We apply the quotient rule:
\[ h^{450 - ?} = h^{250} \]
Since the bases are the same (both are \(h\)), we can set the exponents equal to each other:
\[ 450 - ? = 250 \]
Now, solving for \(?\):
\[ 450 - 250 = ? \]
\[ ? = 200 \]
Thus, the missing exponent is:
\[ \boxed{200} \]