Answer:

Explanation:
Given
See attachment
Required
Determine the surface area
The figure is made up of two cuboids and the surface area of a cuboid is:

Because the bottom part of the upper piece is not visible, the area is calculated as:

This gives:


For the bottom piece:
We calculate its area as
. However, the area of the invisible part will be subtracted.
So, we have:


The total surface area is:

