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Square root of 55

√55 ≈ 7.4162. The square root of 55 is about 7.4162. 55 is not a perfect square, so √55 is irrational: its decimals never end or repeat.

√55 at a glance.
Value7.41619849
Rounded7.4 (1 dp) · 7.42 (2 dp) · 7.416 (3 dp)
Simplest radical form√55
Perfect square?No — between 7² = 49 and 8² = 64
55 squared3,025

Estimating √55 in your head

Start from the nearest perfect square, 7² = 49. 55 is 6 more than that. Divide the difference by twice the root, 14, and add it:

√55 ≈ 7 + 6 ÷ 14 ≈ 7.429

The true value is 7.4162, so the one-step estimate is off by about 0.012. The estimate always comes out slightly high, and it is closest when 55 is near a perfect square. The method is explained in estimating square roots in your head.

Can √55 be simplified?

No. 55 has no perfect-square factor besides 1, so √55 is already in simplest radical form.

Frequently asked questions

What is the square root of 55?

The square root of 55 is about 7.4162. 55 is not a perfect square, so √55 is irrational: its decimals never end or repeat.

Is 55 a perfect square?

No. It lies between 7² = 49 and 8² = 64.

What is √55 in simplest radical form?

√55 is already in simplest form: 55 has no square factor other than 1.

Practise estimating square roots

Nearby: √54 · √56 · all square roots to 150