Square Root of 20

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What is a Square Root?

A number is said to be a square root of a certain number when it produces a quantity or a number when multiplied by itself. The symbol √ is used for square root and is always positive. For instance, the Square root of 25 is 5, which can be simplified with the below diagram:


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Suppose X is a number, and the square root of X is "Y", Then it is denoted as √x = Y. The same can be written as X= Y².

When a positive number is multiplied by itself, it gives the square of the number as positive.

The square root of imperfect squares is tricky, and the answer is always in decimal numbers.

Finding the square root of perfect squares is quite an easy task (like for 4,9, 16,25, and so on) but finding square roots of imperfect squares is a tricky thing. Numbers 3.5, 7, 8, .., 20, and so on are imperfect squares.


Methods for Finding the Square Root

  • Prime factorization method.

  • Long Division method.

The prime factorization method is applied to find square roots of perfect squares, whereas the long division method is applied to find square roots of imperfect squares. Well, both methods can also be used in finding the square root of imperfect squares.


Finding Square Root of 20

Before proceeding with finding square roots, students must be aware of the difference between “a square of a number” and “square root of a number.” For example, when a question asks Square of 20, the answer is 20x 20, i.e., 20² = 400, while the question says the square root of 20 has to be solved in the way mentioned later below.


The square root of 20 is also known as under root of 20 or square root for 20 or radical of 20. The √ is said to be radical, and the number appearing beneath it is radicand. For example, √20, 20 is a radicand.

The value of under root of 20 or root 20 value or Sq. The root of 20 is 4.472135955.

4.472135955 is the square root of 20 or value of under root 20 and is represented as √20 in radical form. The √20 in simplest form is written as 2√5.

Using a calculator and finding the answer is easy, but as a student, knowing the method of finding Sq.root is a must.

This is possible by utilizing two methods: Prime factorization and the long division method. Both methods are simple and are easy to find the square root.

Rounding off, Square root of 20 or √20 = 4.4721. The √20 is an irrational number since it can also be written as 2√5, where √5 is an irrational number.

Proceeding further to find the value of √20.

  1. Prime Factorization Method to Find Square Root of 20

This is the easiest method to find the value of √20  or value of under root √20  

To simplify, let's understand what the prime factorization method is in short – It is breaking down the numbers into a multiplication product of prime numbers.

The prime factorization of 20 is 

20 = 2 x 2 x 5 

In the above example, we can pair two identical prime numbers together and write them as 2², while 5 cannot be paired.

Hence 2² can be written as 2, and 5 is written as √5.

Thus , √20 = √(2 x 2 x 5) 

Therefore, taking 2 outside the root ( as it can be paired together) while 5 can't, we get;

√20 = 2√5

Simplifying this little further, Finding the square root of 5 from the square root table, we get √5 = 2.236

Hence the  answer for √20 = 2√5

= 2 x 2.236

= 4.472.

  1. Long Division Method for Finding the Square Root of 20

Well, we have learned to find the square root of 20 by the prime factorisation method. But to calculate the value of under root 20, it is important to know the value of √5. Even 5 is an imperfect square, and it becomes difficult to find the accurate value of √20 without a square root table.

Therefore for imperfect squares, the long division method is used to find the value of square roots accurately.

The steps for finding the square root of 20 up to 6 decimal places, hence we have taken 20.000000. Put the bar over the paired numbers from the right-hand side:

  1. Take the number whose square root has to be evaluated.

  2. Pair the number from the unit place or the right-hand side of the number.

  3. Take the number that is closer to the square of the number paired. Here 16 is closer to the number 20. Hence, the square root of 16, i.e., 4, should be taken as a divisor.

  4. Dividing the number by 4, the quotient comes to 4, and the remainder is 4. Carry down the next pair of numbers "00". ( The number 20 is written as 20.00000).

  5. Now the quotient 4 should be doubled and written in the divisor place i,e; 8, and in the units place, write a number that comes closer or equal to 400. By hit and trial method, 84 x 4 comes to 336, which is closer to 400.

  6. The remainder is 64, and carrying down the "00", we derive 6400. Now again, double up the quotient (ignoring the decimal, it is 44); hence the divisor will be 88, and in the units place, write a number that comes closer or equal to 6400. By hit and trial method, 887 x 7 = 6209.

  7. The remainder is 191 and again, carrying down "00", it becomes 19100. In the quotient's place, the divisor will be (447*2 = 894). In the unit's place, write a number that comes closer or equal to 19100. Thus the quotient 4.472 is the square root of 20.

  8. If you want to find 2 square root of 20, it comes to 4.472 x 2 = 8.944

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Conclusion:

Finding the square root of 20 is possible by using two methods: Prime factorization and the long division method. Both methods are simple and are easy to find the square root.

FAQ (Frequently Asked Questions)

1. What is a Perfect and Imperfect Square?

Ans. Perfect squares are numbers whose square roots do not include decimals, while imperfect squares are numbers whose square roots include decimal points.

2. Which Method is Usually Preferred to Derive Square Roots of Imperfect Squares?

Ans. Usually, the long division method is used to derive square roots of imperfect squares.

3. Can we call √20 Rational?

Ans. When a number is a perfect square, the square root of that number is rational.√20 is an imperfect square, hence the square root of the 20 is an irrational number.

4. If we are Asked to Derive the Square Root of 20 up to 6 Decimal, How Many Zeros are Required to be Added After the Decimal Point?

Ans. After the decimal, we must add 12 zeros to get the answer of root 20 up to 6 decimals.