√129 ≈ 11.3578
√129 is an irrational number, so its decimals never end or repeat. It sits between 11 and 12 because 11² = 121 and 12² = 144.
| Decimal places | Value |
|---|---|
| 0 | 11 |
| 1 | 11.4 |
| 2 | 11.36 |
| 3 | 11.358 |
| 4 | 11.3578 |
| 5 | 11.35782 |
| 10 (digits) | 11.3578166916 |
129 has no perfect-square factor other than 1, so √129 is already in simplest radical form.
11.3578 × 11.3578 ≈ 128.9996, which is very close to 129.
Need another number? Use the square root calculator (also cube roots and other roots).
| Number | Square root |
|---|---|
| 125 | 11.1803 |
| 126 | 11.2250 |
| 127 | 11.2694 |
| 128 | 11.3137 |
| 130 | 11.4018 |
| 131 | 11.4455 |
| 132 | 11.4891 |
| 133 | 11.5326 |