given the x & y coordinates of a pentagram, how would I determine which point would be closest to a line to symmetry?

clarify:

I have a 5 pointed star and I want to calculate which outer point would best make a line of symmetry. So, basically, which triangle of the star should I draw a line down from to make the star look most equal on both sides? or which triangle is the "top" one or "oddball" one? How would I go about calculating that?

Areas? or Angles? or both?

I've done it with just the angles, calculating the angle of each outer star point and picking the angle that is furthest from all the rest when they are all compared with each other but I'm concerned I should be calculating areas. Does angle account for area in a closed shape like a pentagram?