Square Root – Prime Factorisation Method (Part 1)

Table of Contents

• Finding Square Root
• Prime Factorisation Method
• Summary
• What’s Next?

In the previous segment, we learnt how to find the square root of a number using repeated subtraction. In this segment, we will learn an easier and better method to find the square root.

Finding square root

The square root of a number can be found by two methods other than repeated subtraction:

• Prime factorisation method
• Long division method

How to find the square root of a number by prime factorisation?

Let us understand the following steps of the prime factorisation method by finding the square root of 225.

Step 1: Find the prime factors.

3	225
3	75
5	25
	5

Step 2: Make pairs of the same prime factors.

225 = 3 x 3 x 5 x 5

Step 3: Choose one number from each pair and multiply.