Sorry, but this is a bit confused. Perhaps if you define what you mean by all those "somethings" it would be clearer what you're asking. Are you asking about lines perpendicular to lines, or perpendicular to circles, or 3-dimensional surfaces, or what? By "point slope method" are you talking about how to find the equation of a line given two sets of coordinates? Finally what do you mean by finding a line perpendicular to "something ...passing through 2 given coordinates?" Perhaps if you gave an example we could be of better help.