To determine whether \( \sqrt{9} \) is rational or irrational, we first calculate the square root:
\[ \sqrt{9} = 3 \]
The number 3 is an integer, and all integers are also rational numbers because they can be expressed as a fraction (for example, \( 3 = \frac{3}{1} \)).
Thus, \( \sqrt{9} \) is a rational number.
Summary:
- \( \sqrt{9} = 3 \)
- 3 is a rational number (can be expressed as \( \frac{3}{1} \))
- Therefore, \( \sqrt{9} \) is rational.