A girl walks 4 km towards west, then she walks 3 km in a direction 30° east of north and stops. Determine the girl’s displacement from her initial point of departure.

let O be the initial position and B be the final position of the girl.

Position of girl will be as shown in figure:

Hence, and BAO = 60°

Now, by using triangle law of vector addition,

Hence girls displacement from initial to final position is :