Tip-to-Tail Method

Tip-to-Tail Method
We can add any two vectors, A and B, by placing the tail of B so that it meets the tip of A. The sum, A + B, is the vector from the tail of A to the tip of B. Note that you’ll get the same vector if you place the tip of B against the tail of A. In other words, A + B and B + A are equivalent.


reference: http://www.sparknotes.com/testprep/books/sat2/physics/chapter4section2.rhtml