The position vector f three consecutive vertices of a parallelogram are `hat(i) + hat(j) + hat(k), hat(i) + 3hat(i) + 5hat(k)` and `7hat(i) + 9hat(j) + 11 hat(k)` Find the position vector of the fourth vertex.

Answer

`7(hat(i) + hat(j) + hat(k))`