The simple way to find square roots is as follows:
Suppose take 1225.
Take last two digits as pair.
25 is one pair and 12 is one pair.
unit digit is 5 so the unit digit of its suares also be 5.
write 5 in units place.
Now see next numbers,
12. It is in between 3 and4.
4 is big so take lesser value there you got your answer 35.
Like this also you can find squares roots.