This question is really pissing me off because I don't understand it. I know how to do it but don't understand the reasoning: Find an equation of the line through the point (4,5,5) that meets the line (x-11)/3=(y+8)/-1=(z-4)/1 at right angles. I found out that you have to do the dot product of (4,5,5) and that equation but I don't understand why you don't need the direction vector for the other equation to find the answer. Also why couldn't you just do (4,5,5) dot (11,-8,4)?????????