Question: The number $\sqrt{9}$ is ______ because
1. The problem asks us to determine the nature of the number $\sqrt{9}$.
2. Recall that the square root of a number $x$ is a value that, when multiplied by itself, gives $x$.
3. The square root of $9$ is $3$ because $3 \times 3 = 9$.
4. Since $3$ is a whole number and can be expressed as a fraction $\frac{3}{1}$, it is a rational number.
5. Therefore, $\sqrt{9} = 3$ is a rational number.