Example 13 Find the square root of 12.25.Rough
64 × 4 = 256
65 × 5 = 325
Therefore,
Square root of 12.25 = 3.5
Individual Steps are explained
Step 1:
Write the number
We make pairs from right.
For numbers before decimal point,
we start from right and make pairs
So, 12 is a pair
For numbers after decimal point,
we start from the right of decimal point and make pairs
So, 25 is a pair
Step 2:
Now we find that number whose
square is less than or equal to 12.
2 × 2 = 4
3 × 3 = 9
4 × 4 = 16
Since 16 > 12, we use 3 × 3.
So writing 3 on left side & top.
& 9 below 12
Now we find remainder,
12 − 9 = 3
Step 3:
Since next is decimal point
We put a decimal point on top
Step 4
Pair 25 comes down
So, our number is now 325
Step 5
We multiply the number above by 2
& add a blank after it
So, we write 3 × 2 = 6
6 _
Step 6
Find a number which is less than
Or equal to 325
63 × 3 = 189
64 × 4 = 256
65 × 5 = 325
Since 65 × 5 = 325. We use that
Thus,
Square root of 12.25 = 3.5

Made by

Davneet Singh

Davneet Singh is a graduate from Indian Institute of Technology, Kanpur. He has been teaching from the past 12 years. He provides courses for Maths and Science at Teachoo.