Question

find the greatest 4 digit number which is perfect square

Answer 1

9999 is largest 4 digit number, and 100^2 is 10000, or 1 greater than the largest 4 digit number. This means that the closest square root of the largest perfect square is most likely 99. So 99^2 (9801)is the largest perfect square of four digits.

Answer 2

Given that,

The greatest 4 digit number which is perfect square.

We know that.

The smallest  4 digit number is 1000.

The greatest 4 digit number is 9999.

We know that,

The square of 100 is 10000 or 1 more noteworthy than the biggest 4 digit number.

So, the closest square root of the largest perfect square is 99. So. The square of 99 is

$(99)^2=9801$

We can say that, the largest closest square of four digits is 99.

Hence, The greatest 4 digit number is 9999 and it is the closest square of 99.