Finding the Slope of the Perpendicular Line to the Line Through the Two Points

To determine the slope of a line passing through a pair of points, one can use the equation (y2-y1)/(x2-x1). If another line is perpendicular to this one, the slope of that line is the negative reciprocal of the slope of the first line. Hence, if the slope of the initial line is represented as a/b, the slope of the perpendicular line will be -b/a.