Formula? Open your mechanics of material book. V shape you can find the moment of inertia of a big triangle, minus smaller triangle. U, will probably be a lot harder to do doing it by hand. I do have Risa Section that will calculate whatever custom section you have.
autoCAD will calculate the section properties. You will need to have the centroid of the section positioned at the origin of the coordinate system. I have used it in the past with great success.
As with any program, you need to know how to do it by hand before using ia program to calculate the properties for you.
Risa Section, you just need to know how to draw . It will give you Ix, Iy, and weak axis I which is pretty hard to do by hand if you have a non symetrical section.
If your plates are thin, then you need to calculate properties according to AISI's Cold Formed Steel Design Manual. The manual has detailed methods for calculating properties of bent shapes, taking into account buckling characteristics of thin sections.