Square Root Of Perfect Squares

Method:

I request the students to remember the square of numbers from 1 to 10.

Number:     1    2    3    4     5      6      7     8     9     10

Squares:    1   4     9    16    25    36    49   64   81    100

Also the same applies for numbers from 10 to 100 and the numbers ending in 5.

Let us take an example:

Find the square root of 7744:

The number ends in 4 so looking at the above table we can conclude that the square root ends in either 2 or 8.

Next we take the complete number 7744. This number lies between 6400 which is square of 80 and 8100 which is square of 90. So our possible answer lies in between 80 and 90. i.e.: 81,82,83,84,85,86,87,88,89. But only two numbers end in 2 and 8 i.e. 82 and 88.

Now in betwenn 82 and 88 what is the answer. So in the previous lessons, we learned how to find the square of numbers ending in 5. Similarly we find the square of 85 which is = 7225. 

Lastly as our number 7744 is more than 7225 our answer is obviously 88.

Similarly try for 9801.