Question

find the greatest number of 4 digits number which is a perfect square

Answer 1

Here we need largest 4 digit number which is a perfect square.

The largest 4 digit number is 9999. But it is not a perfect square.

Let us consider the smallest 5 digit number.. it is 10000.

Here 10000 is a perfect square(100*100=10000).

As the smallest 5 digit number is a perfect square of 100, the largest 4 digit perfect square should be 99*99.

So the required answer is 9801

@skb

Answer 2

99×99=9801, since 100×100=10000which is a five digit number. Since the number has 4 digits, its square root will always have two digits. Thus,greatest 4-digit number which is a perfect square is 9801.