Question

state the triangle law of vector addition and explain vector addition is commutative and associative​

Answer 1

The law states that the sum of vectors remains same irrespective of their order or grouping in which they are arranged.

Consider three vectors ,  and  

Applying "head to tail rule" to obtain the resultant of (+ ) and (+ )

Then finally again find the resultant of these three vectors :

This fact is known as the ASSOCIATIVE LAW OF VECTOR ADDITION.