Addition of vectors

On the screen, you see AB and AC in blue color. You can change the value of these vectors by moving the point B and C. AB and AC vectors are represented as u and v respectively. Value of any vector does not depend upon its position. Value depends upon direction and length. So we have also drawn v’ and u’ (shown in figure). Move the points B and C and observe how the values get changed.
1. What relation do you observe between u, v and w? 2. Observe how it is called triangle method of vector addition? 3. Observe how it is called parallelogram rule of addition?