Question

which of the following is a perfect square​

Answer 1

The perfect squares are the squares of the whole numbers: 1, 4, 9, 16, 25, 36, 49, 64, 81, 100 … So, from above given numbers, 1, 36, 49, 81, 169, 625, 900 and 100 are perfect squares. If the last digits of a number is 5, its square ends in 5 (in fact, the last two digits must be 25).