Maybe I just don't get math...

it 3d. not 2d.

Surface area = 64
Just tryin to help ya

I got the surface area before I made this lol

But thanks

Surface area = 336
4*((4*7)+(5*8)) + (8*8)

It's the correct perspective for oblique projection

Oh god

That is not a job done wrong. That is a 3D shape.

The length and width are the same, so if you looked on the bottom, you should see a square, but it's a rectangle on the bottom and I don't know WHY

The apparent shortening is due to representing a 3D object in oblique projection. The 'depth' is half its real value as a way of making the object look three dimensional.
https://en.m.wikipedia.org/wiki/Oblique_projection