Let $P = (-5, 3, 4)$, $Q = (-6, 0, 3)$, $R = (-7, 1, 6)$ and $S = (-4, 2, 2)$. Let $A$ be the line passing through $P$ and $Q$, and let $B$ be the line passing through $R$ and $S$.
a) What is the distance between $R$ and $A$?
b) What is the distance between $A$ and $B$?
I am quite confused on how to start with this problem. Firstly, I am not entirely sure how I will find the distance between the point and the line. Would that distance simply be the normal vector multiplied by the projection? If so, how exactly would I calculate the projection here? No equations for the lines are given so I am quite confused.
Also, for the shortest distance between two lines, will it be a similar approach of finding the normal vector and projection?
I am not entirely sure how to proceed here. Any help would be highly appreciated!