Find the largest number of 2 digits which is a perfect square.
The largest 2-digit perfect square is 81, which equals 9². Two-digit numbers range from 10 to 99. The next perfect square, 10² = 100, is already a 3-digit number. Therefore, 9² = 81 is the highest perfect square that still falls within the two-digit range.
Question:
Find the largest number of 2 digits that is a perfect square.
Solution:
The first three-digit number (100) is a perfect square. Its square root is 10.
The number before 10 is 9.
Square of $9=(9)^{2}=81$
Thus, the largest 2-digit number that is a perfect square is 81.