What is the square root of 81

The short answer is \( \sqrt{ 81 } = 9 \).

If that's all you're looking for, thanks for coming by. But if you're interested in the hows and whys behind square roots, continue reading and we'll tell you all about the square root of 81.

81 is a perfect square

Let's look at some math.

$$ \LARGE \sqrt{ 81 } = 9 $$

The important part is to the right of the equals sign. Since the square root of 81 is a whole number, that means that 81 is a perfect square. The square root of 81 is 9, which is a whole number.

The next perfect square greater than 81 is 100. The previous perfect square less than 81 is 64.

Square root of 81 as an exponent

Any square root can be converted to a number with a fractional exponent. In the case of 81 the following two values are equal.

$$ \LARGE \sqrt{ 81 } = 81^{^1/_2} $$

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