Prove that squaring a number will give a number that is divisible by 4

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!

Eight-squared would be equal to 64, which is divisible by four:
64/4=16

178.3 mm²

Step-by-step explanation:

Surface area = Base area + 3 x side triangles area

Sₐ = 43.3 + 3 x (1/2 x (10 x 9)) = 43.3 + (3 x 45) = 178.3