What is the square root of 81?

√81 = ±9

9

9

√81 = ± 9

It is a rational number that can be factored. ( 9 X 9) =81.

9 is the square root. Using the "Associative Property" we can also say 3 X 3 X 3 X 3 = 81. There are no other factors.

I know, I used my calculator!

√81 = √ 9 x 9
= 9

9


9*9=81

9

is 9 because 9 squared is 81.

The square root of 81 is 9 given that 9*9= 81! If you are trying to calculate roots and sometimes encounter difficulties, you can rationalise them as smaller roots. For example: The square root of 81 = the square root of 9 * the square root of 9. The square root of 9 = 3 as 3*3=9. Therefore the square root of 81 = 9*9 =81! An alternative is -9 because - * - = + and thus -9*-9=+81!