Prove points are coplanar 
I have that $AX = BX, AW=BW, AY = BY, AZ=BZ$
No matter how, I can't imagine that this points necessarily need to be coplanar, but the exercise asks me to do it: prove that $W,X,Y,Z$ are coplanar.
Any help?

Can you show that WZ is perpendicular to AB, and that the midpoint of AB is coplanar with WZ? The same argument will apply to XY and that's it. You will have WZ and XY coplanar with the midpoint of AB and hence are coplanar.
