√20 ≈ 4.4721
√20 is an irrational number, so its decimals never end or repeat. It sits between 4 and 5 because 4² = 16 and 5² = 25.
| Decimal places | Value |
|---|---|
| 0 | 4 |
| 1 | 4.5 |
| 2 | 4.47 |
| 3 | 4.472 |
| 4 | 4.4721 |
| 5 | 4.47214 |
| 10 (digits) | 4.4721359550 |
20 = 4 × 5 and √4 = 2, so √20 = 2√5.
4.4721 × 4.4721 ≈ 19.9997, which is very close to 20.
Need another number? Use the square root calculator (also cube roots and other roots).
| Number | Square root |
|---|---|
| 16 | 4 |
| 17 | 4.1231 |
| 18 | 4.2426 |
| 19 | 4.3589 |
| 21 | 4.5826 |
| 22 | 4.6904 |
| 23 | 4.7958 |
| 24 | 4.8990 |