What's the surface area formula for wedges?

Answer 1

I assume you have
a rectangular base and sloping face
two triangular sides
a rectangular face at the back.

I'm sure you know how to find each kind of area, so just add them up.

Answer 2

As for the surface area, the main problem is the upper surface - it's a curved surface. This is a matter of advanced mathematics, and I have long forgotten it.

Therefore, I need the full formula, not the procedure