This is not true with every numbers, but here you need only one example, so it could be many, one of them are:
Proof:
Number 6,
--Squaring of 6 = 6² = 36
--Now divide by 4, = 36/4 = 9 [ number is whole, so it is divisible ]
Number 8,
-- Squaring of 8 = 8² = 64
--Now divide by 4, 64/4 = 16 [number is whole, so it is divisible ]
Here, I gave you two examples, but you can create some more, by any even number squaring like, 2, 4, 6, 8, 10, 12, 14
Hope this helps!