Square root of 70
√70 ≈ 8.3666. The square root of 70 is about 8.3666. 70 is not a perfect square, so √70 is irrational: its decimals never end or repeat.
| Value | 8.36660027 |
|---|---|
| Rounded | 8.4 (1 dp) · 8.37 (2 dp) · 8.367 (3 dp) |
| Simplest radical form | √70 |
| Perfect square? | No — between 8² = 64 and 9² = 81 |
| 70 squared | 4,900 |
Estimating √70 in your head
Start from the nearest perfect square, 8² = 64. 70 is 6 more than that. Divide the difference by twice the root, 16, and add it:
√70 ≈ 8 + 6 ÷ 16 ≈ 8.375
The true value is 8.3666, so the one-step estimate is off by about 0.008. The estimate always comes out slightly high, and it is closest when 70 is near a perfect square. The method is explained in estimating square roots in your head.
Can √70 be simplified?
No. 70 has no perfect-square factor besides 1, so √70 is already in simplest radical form.
Frequently asked questions
What is the square root of 70?
The square root of 70 is about 8.3666. 70 is not a perfect square, so √70 is irrational: its decimals never end or repeat.
Is 70 a perfect square?
No. It lies between 8² = 64 and 9² = 81.
What is √70 in simplest radical form?
√70 is already in simplest form: 70 has no square factor other than 1.
Practise estimating square rootsNearby: √69 · √71 · all square roots to 150