Vectors-Types Of Vectors

Angle between two vectors

To find angle between two vectors, the two vectors from a point are drawn such that they should either co initial or co terminal. The shortest angle obtained in this way, is the angle between the vectors.
                

If given vectors are not co initial or co terminal, then slide any one of the vector parallel to its direction to make them co initial or co terminal and measure angle as shown below. 
       

So the angle between \(\vec A\) and \(\vec B\) is not 120°.