Question

find the greatest four digit no whichis a perfect square​

Answer 1

The greatest four digit number is 9999 whose square root is 99.99. Now the integer less that 99.99 is 99 whose square is 992 =9801. So the greatest four digit perfect square number is 9801.

Answer 2

Answer:

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.