1. The problem statement, all variables and given/known data Two vectors are given as A=3x+y-2z and B=x-z. A third vector C lying in the yz-plane is perpendicular to A and its magnitude is 7 units. Find the angle between C and B. 2. Relevant equations cross and dot product 3. The attempt at a solution I can't imagine of way, a vector lying on the yz plane can be perpendicular to a 3d vector which has 3 nonzero unit vector components. An explanation on this is much appreciated.