A triangle is a Polygon!

While doing my Physics lab, half an hour before class, it asks me this question: "How many vectors may be added by the polygon method? Are other methods of vector addition limited to the number of vectors that can be added? Explain."

How dare it say that a triangle isn't a polygon! It's the smallest polygon thank you very much and the polygon method is derived from the triangle method. It never says that anywhere in the book. One could argue, the proofs are missing. I want Calculus-based Physics! If we had that at Small U, I could learn something instead of reviewing math that I learned a long time ago.

Grrrrr... I learned too much math for this course to be useful/fun.