help again i just started and im having trouble lol

Answer:
3) [tex]\sqrt{81}[/tex]
Step-by-step explanation:
[tex]\sqrt{81}=9[/tex]
9 is a rational number since it can be expressed as a fraction ([tex]\frac{9}{1}[/tex])
When you square root the other options, 79, 80 and 82, you'll get an answer that goes on forever.