I have this question. I'll go through the previous parts so you have an idea of what it's asking.

Givenu= (4, 0, -2),v= (3, 1, -1),w= (2, 1, 6) find

(a) the angle betweenuandw(98 degrees)

(b) the component ofualongv(14/11)

(c) the projection ofvalongw1/41(2,1,6) i.e (2/41, 1/41, 6/41)

And finally (d) a vector constructed from (c) and perpendicular tow

I'm struggling with this final part... I just don't understand it..