The square root of a number (let’s say 25) refers to that number which when multiplied by itself will give the result as the given number (i.e. 25). In our case, the number is 5. We see that 5, when multiplied by itself (i.e. 5), will result in 25. Therefore, 25 is known as the square of 5, and 5 is known as the square root of 25.
Note:
(1) Multiplying two negative numbers will also result in a positive number. Therefore, (-5)*(-5) is also equal to 25. So, -5 is also a square root of 25. But, in general, we assume the square roots of a positive number to be a positive number.
(2) The square root of 1 is always 1.
We represent the square root of a number by a radical sign (√). Example: √36 = 6 (because 6 x 6 = 36)
Note:
(3) Finding the square root of a negative number (i.e. when the negative sign is inside the radical sign i.e. √-36) is a bit complex and is out of context for this article.
(4) if the minus sign is given outside the radical sign (i.e. -√36), then the answer will always be -6.
There are two types of numbers:
Numbers which are a perfect square: Product of an integer with itself. For example, 9*9 = 81.
Numbers which are an imperfect square: Multiplying any number with itself. For example, 2.236*2.236 = 5.
Finding the square root of an imperfect square is a little more difficult than finding the square root of a perfect square number. We will be covering both the topics in this particular article. But before that, we have to understand what square roots are used for.
For example, Rhea is looking for an apartment in Delhi. She is looking for a 2 bedroom apartment where she can live with her sister. A few phone calls later, she has shortlisted two places after seeing their pictures online. One is 1600 square feet with a balcony and the other is 2500 square feet with two balconies. Now, she can easily gauge the size of the first apartment as 40 feet by 40 feet. The second apartment would be 50 feet by 50 feet. This was just an example. Square roots are used for multiple purposes like these.
Now coming to our main topic, i.e., how to find the square root of a number?
(A) Perfect Square Numbers:-
Before finding the square roots of a number, we have to know the squares of the first 9 natural numbers.
1*1 = 1
2*2 = 4
3*3 = 9
4*4 = 16
5*5 = 25
6*6 = 36
7*7 = 49
8*8 = 64
9*9 = 81