To check which are the perfect squares we have factorise the number and make group of two if no factor remains after grouping then given number is perfect square.
9 = 3×3
Form group of number 3 thus is perfect square
24 = 3×2×2×2
As only pair of 2 form group, 3 and 2 left behind . So, 24 is not a perfect square
16 = 2×2×2×2 . There are two pairs of 2 and nothing left behind .
Thus 16 is a perfect square
200 =2×2×5×5×2 , there are pairs of 2 and 5, but number 2 left without pair
Therefore 200 is not a perfect square
169 = 13×13 ,form pair of 13 . Hence, is a perfect square
625=5×5×5×5, forms two pair of 5 . Therefore is perfect square
