Question

If side of a cube is double then how many times its total surface area will increase?

Answer 1

Let $a$ be the side of the cube.

Then its total surface area will be $S_1=6a^2$.

Now if the sides are doubled then the length of new sides be $2a$.

And the total surface area will be $6\times (2a{)}^2=4\times 6a^2=4\times S_1$.

So surface area will be four times the original surface area.