What is the square root of 81?

The square root of a number is a value that, when multiplied by itself, gives the original number. In this case, the square root of 81 is being sought. To determine this, we need to find a number that, when squared (multiplied by itself), equals 81.

Calculating, we find that 9 multiplied by 9 equals 81 (9 x 9 = 81). Thus, the square root of 81 is indeed 9. This confirms that the answer is 9, which corresponds with the correct choice provided. The other options do not equal 81 when squared, as 7 squared (49), 8 squared (64), and 10 squared (100) yield values far from 81. Therefore, identifying 9 as the square root is accurate and aligns with the definitions and properties of square roots.