We can solve this problem by division.  Alternatively, we can multiply the numerator and denominator by 5, yielding $\frac{45}{10}$.  Since dividing a number by 10 shifts the decimal point to the left by one place, this yields $\boxed{4.5}$.
Question:
What is $\frac{9}{2}$ expressed as a decimal?
Answer:
Let's think step by step.

user
4.5
What is $\frac{9}{2}$ expressed as a decimal?
test