Question

Find the largest number of 3 digits which is a perfect square.

Answer 1

The largest 3 digit number is 999.

The number whose square is 999 is 31.61.

Thus, the square of any number greater than 31.61 will be a 4 digit number.
Therefore, the square of 31 will be the greatest 3 digit perfect square.

${31}^2=31\times 31=961$