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Square root of 108

√108 ≈ 10.3923. The square root of 108 is about 10.3923, which simplifies to 6√3. 108 is not a perfect square, so √108 is irrational: its decimals never end or repeat.

√108 at a glance.
Value10.39230485
Rounded10.4 (1 dp) · 10.39 (2 dp) · 10.392 (3 dp)
Simplest radical form6√3
Perfect square?No — between 10² = 100 and 11² = 121
108 squared11,664

Estimating √108 in your head

Start from the nearest perfect square, 10² = 100. 108 is 8 more than that. Divide the difference by twice the root, 20, and add it:

√108 ≈ 10 + 8 ÷ 20 ≈ 10.4

The true value is 10.3923, so the one-step estimate is off by about 0.008. The estimate always comes out slightly high, and it is closest when 108 is near a perfect square. The method is explained in estimating square roots in your head.

Simplifying √108

Find the largest perfect square that divides 108: it is 36, since 108 = 36 × 3. Take its root outside: √108 = √36 × √3 = 6√3.

Frequently asked questions

What is the square root of 108?

The square root of 108 is about 10.3923, which simplifies to 6√3. 108 is not a perfect square, so √108 is irrational: its decimals never end or repeat.

Is 108 a perfect square?

No. It lies between 10² = 100 and 11² = 121.

What is √108 in simplest radical form?

√108 = √(36 × 3) = 6√3.

Practise estimating square roots

Nearby: √107 · √109 · all square roots to 150