Tetrahedron teabags

I love these teabags! A nice question: if taken apart what is its shape? Next question, if you want to make a large tetrahedron from the same pattern with a piece of A4 paper (or letter-size paper or whatever), what should the dimensions of your template be? Will you account for the overlap? I haven't tried it yet, but I think there will a nice use of √3 in here somewhere.