Question:
Find the largest number of 3 digits which is a perfect square.
Solution:
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.
$31^{2}=31 \times 31=961$