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Square root of 109

√109 ≈ 10.4403. The square root of 109 is about 10.4403. 109 is not a perfect square, so √109 is irrational: its decimals never end or repeat.

√109 at a glance.
Value10.44030651
Rounded10.4 (1 dp) · 10.44 (2 dp) · 10.440 (3 dp)
Simplest radical form√109
Perfect square?No — between 10² = 100 and 11² = 121
109 squared11,881

Estimating √109 in your head

Start from the nearest perfect square, 10² = 100. 109 is 9 more than that. Divide the difference by twice the root, 20, and add it:

√109 ≈ 10 + 9 ÷ 20 ≈ 10.45

The true value is 10.4403, so the one-step estimate is off by about 0.01. The estimate always comes out slightly high, and it is closest when 109 is near a perfect square. The method is explained in estimating square roots in your head.

Can √109 be simplified?

No. 109 has no perfect-square factor besides 1, so √109 is already in simplest radical form.

Frequently asked questions

What is the square root of 109?

The square root of 109 is about 10.4403. 109 is not a perfect square, so √109 is irrational: its decimals never end or repeat.

Is 109 a perfect square?

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

What is √109 in simplest radical form?

√109 is already in simplest form: 109 has no square factor other than 1.

Practise estimating square roots

Nearby: √108 · √110 · all square roots to 150