What’s the right answer?

I will give you the formula and teach you how to solve this. Let’s start with finding the area of both the right triangles.
The formula is, base x height / 2 = area
Triangle 1 - 2x8/2 = 16/2 = 8
Triangle 2 - 2x8/2 = 16/2 = 8
Rectangle - 8x3 = 24
Add them up: 24 + 8 + 8 = 40 square feet
I hope this wasn’t to confusing

40 square feet all you need to do for this shape is multiply the full top length and the side length :)