Perpendicular means the slopes are opposite inverse of each other If line a is slope 2, the perpendicular line to Line a would have a slope - 1/2 Difference in y over difference in x gives slope. If they are opposite inverse values the lines are perpendicular. ( in this case the answer is true.)
The point has a high leverage as it would act as an infinitesimal point that will have a very huge/drastic impact on the fit of the model, and this impact can be seen in such ways as listed below :
Smaller coefficient of determination
Higher sum of squares error
removing this point will eliminate these drastic impact and make the correlation to be better.