Question

Can anyone help me please ?

Answer 1

Choice `b`.

Explanation:

All right. Before doing anything else, here is the flattened version of a cylinder:

Now, we see that we are basically asked to find the red area.

Since we are given that `h=20cm` and `d=20cm`

In order to figure out the width, we have to figure out the circumference of the base of the cylinder.

Now, remember that: `C=pid`

Therefore, `C=20pi`

We can now apply this to our formula `A=wh`

=>`A=20pi*20`

=>`A=400pi`

=>`A~~1256.63706144`

We see that this is the closest to choice `b`.