Give a condition that three vectors and form the three sides of a triangle. What are the other possibilities?

Given that, and are three sides of a triangle.

Hence from the above figure we get,

AB = , BC = and AC =

So

[since]

[Since CA = - AC]

Triangle law says that, if vectors are represented in magnitude and direction by the two sides of a triangle is same order, then their sum is represented by the third side took in reverse order. Thus,

or or