Square Root of 20 — sqrt(20) = 2sqrt5

The square root of 20 is 2sqrt5. In decimal form, sqrt(20) approximately 4.472136 (irrational). This page shows the exact value, simplified radical, decimal to 20 places, prime factorisation, and a visual number line....

20 = ?

SQUARE ROOT OF 20

2√5

4.4721359550

Irrational — cannot be expressed as a fraction

Exact form

2√5

Decimal (4dp)

4.4721

Decimal (10dp)

4.4721359550

Is perfect sq?

No

√20 ²

20 ✓

Between

4 and 5

DECIMAL PRECISION

204.4721359550

STEP-BY-STEP

1

Prime factorisation: 20 = 2 × 2 × 5

2

Simplified radical form: 2√5

3

4² = 16 < 20 < 25 = 5² → lies between 4 and 5

4

204.4721359550...

FUN FACT

sqrt(20)=2*sqrt(5) approximately 4.47213... Simplifies because 20=4*5.

NUMBER LINE (√204.4721)

4

5

20

SQUARE WITH AREA = 20

Area = 20

20

4.472

204.472

NEARBY PERFECT SQUARES

4= 22² = 4
9= 33² = 9
16= 44² = 16
25= 55² = 25
36= 66² = 36
49= 77² = 49

SQUARE ROOT LAWS

√20 × √20= 20
(√20)²= 20
√(20 × 4)= 2√20 ≈ 8.9443
√(20/4)= √20/2 ≈ 2.2361
√20 × √21≈ 20.4939
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HOW TO CALCULATE

  1. 1

    Find the prime factorisation of 20: 20 = 2 x 2 x 5. Check for repeated prime factors.

  2. 2

    Simplify: pull out any pairs of identical prime factors. Result: 2sqrt5. Pairs were extracted to simplify the radical.

  3. 3

    Locate sqrt(20) between integers: 4 squared = 16 and 5 squared = 25. Since 16 < 20 < 25, sqrt(20) lies between 4 and 5.

  4. 4

    Calculate decimal: sqrt(20) approximately 4.4721359550. Verify by squaring: (4.472136) squared approximately 20.0 = 20.

WORKED EXAMPLE

sqrt(20): not a perfect square. Factorisation: 20 = 2 x 2 x 5. Simplified: 2sqrt5. Decimal: sqrt(20) approximately 4.4721359550.

FREQUENTLY ASKED QUESTIONS

OTHER SQUARE ROOTS

Bold bordered = perfect squares (exact integer result)

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Last updated: April 28, 2026 · Verified by EagleCalculator team · Eagle-eyed accuracy for every calculation.