Square Root Of 20 – Explanation And Methods - Vedantu

The concept of square root of 20 plays a key role in mathematics and is widely applicable to both real-life situations and exam scenarios.

What Is Square Root of 20?

A square root of 20 is a number that, when multiplied by itself, yields 20. The square root is represented with the √ symbol, i.e., √20. You’ll find this concept applied in areas such as algebra, geometry, and word problems in Mathematics.

Key Formula for Square Root of 20

Here’s the standard formula: \( \sqrt{20} = 2\sqrt{5} \) (in simplest radical form)

Cross-Disciplinary Usage

The square root of 20 is not only useful in Maths but also plays an important role in Physics, Computer Science, and daily logical reasoning. Students preparing for JEE or NEET will see its relevance in distance, area, and measurement questions.

Is 20 a Perfect Square?

No, 20 is not a perfect square. A perfect square has integer square roots (like 4, 9, 16), but √20 is not an integer. This means its square root value will always be a decimal or in radical form.

How to Find the Value of Square Root of 20?

The value of the square root of 20 can be found by estimation, division method, or using the prime factorization method:

Form	Answer
Radical Form	√20
Simplest Form	2√5
Decimal (approx.)	4.472

Step-by-Step Illustration

1. Simplify using Prime Factorization: 1. Write 20 as product of prime factors: 20 = 2 × 2 × 5 2. Pair the same numbers: (2 × 2) forms a pair; 5 remains 3. Take one number from the pair outside the root: 2 4. Final Answer: √20 = 2√5
2. Estimate by Nearest Perfect Squares: 1. √16 = 4 and √25 = 5 2. So, √20 is between 4 and 5. 3. Calculate (optional): √20 ≈ 4.472
3. By Long Division: 1. Place number 20 under bars (20.0000...) 2. Find a number whose square is ≤ 20 (4 × 4 = 16) 3. Place 4 in quotient; Subtract 16 from 20 (remainder 4); bring down next pair of zeros 4. Double the quotient (8), use as new divisor, find next digit, continue. 5. After a few steps: √20 ≈ 4.472

Speed Trick or Vedic Shortcut

Here’s a quick shortcut to simplify √20 during exams:

1. Break 20 into multiples: 20 = 4 × 5
2. Write √20 = √4 × √5 = 2√5

For other roots, apply similar logic! See Vedantu's square root tricks for more tips.

Is Square Root of 20 Rational or Irrational?

The square root of 20 is an irrational number. Its decimal expansion never terminates or repeats (4.472135954...). It cannot be written as an exact fraction. This is true for all non-perfect squares.

Visual Representation of √20

To see where √20 lies, plot it on the number line between 4 and 5. Use number line methods for practice.

Uses and Word Problems with √20

The square root of 20 is seen in real-life geometry, for example:

• The diagonal of a rectangle with sides 2 units and √20 units
• Finding the side of a square when area is 20 sq units

Try problems with area of squares or Pythagoras calculations where the answer comes as √20!

Try These Yourself

• Express √20 in its simplest radical form.
• Calculate the value of 2 × √20.
• Show why √20 is irrational.
• Compare √20 to √16, √25, and √10.

Frequent Errors and Misunderstandings

• Assuming √20 = 4 or 5 (it is a decimal, not an integer).
• Forgetting to simplify to 2√5 in board exams.
• Using rounded approximations (4.47) when exact forms (2√5) are needed.

Relation to Other Concepts

The square root of 20 connects closely with perfect squares, other imperfect roots, and prime factorization in algebra. Understanding this makes roots easier in algebraic expressions and geometry.

Classroom Tip

A quick way to remember √20’s simplest form: if the number inside has a perfect square, split it! For example, √20 = √4 × √5 = 2√5. Vedantu’s teachers often use such cues in live doubt-solving classes.

Related Roots and Comparison Table

Root	Simplest Form	Decimal
√16	4	4.000
√20	2√5	4.472
√25	5	5.000
√10	(Cannot be simplified)	3.162

We explored square root of 20—from definition, formula, examples, mistakes, and connections to other subjects. Continue practicing with Vedantu’s theory on squares and square roots and use the square root calculator to master this concept!

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