4,624 = 682
If the number with the digits reversed can have a leading 0 so that it is a 1-digit number, then 16. Otherwise 13.
The biggest number with 6 digits that is a perfect square is 999,999. When squared, it becomes 999,999,000,001.
x64 is not a perfect square any number if it is a 3-digit perfect square and ending with 4 it can be 144,324 ,484 and 784 because the number is ending with 4 but the tens digit is not matching to any of the option so it is not a perfect square
81
69
49
Every square of a 4 digit number has more than four digits.
81...........
729
81
No. The smallest 2 digit number is 10 the smallest 3 digit number is 100 - so the question is whether (100-10) is a perfect square? No - 90 is not a perfect square. 8x8 is 64 and 9x9 is 91, not 90.
1600 (square of 40)