√81 = 9
81 is a perfect square: 9 × 9 = 81, so √81 = 9 exactly (no decimals).
Need another number? Use the square root calculator (also cube roots and other roots).
| Number | Square root |
|---|---|
| 77 | 8.7750 |
| 78 | 8.8318 |
| 79 | 8.8882 |
| 80 | 8.9443 |
| 82 | 9.0554 |
| 83 | 9.1104 |
| 84 | 9.1652 |
| 85 | 9.2195 |