Square Root Calculator › Square root of 81
Square Root of 81
√81 = 9
81 is a perfect square: 9 × 9 = 81. Its square root is the whole number 9.
| Number | 81 |
| Square root (decimal) | 9 |
| Simplified radical | 9 |
| Perfect square? | Yes |
| Rational? | Yes |
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Frequently asked questions
Is 81 a perfect square?
Yes. 81 is a perfect square because 9 × 9 = 81, so √81 = 9.
What is the square root of 81 in simplest radical form?
√81 simplifies to the whole number 9.