Answer:
[tex] \: \sqrt{81 } = 9[/tex]
Step-by-step explanation:
[tex] \sqrt{81 } = \sqrt{3 \times 3 \times 3 \times 3} \\ = 3 \times 3 \\ =9[/tex]
You have to prime factorise 81 and then you will get 9 as the answer.
9
9 x 9 = 81