To determine if a line is perpendicular to another, you must first determine the slope... m = y1-y2/x1-x2 m of FK = 3-5/3-6 = -2/-3 = 2/3 m of FJ = 3-2/3-8 = 1/-5 m of FL = 3-0/3-5 = 3/-2 m of KJ = 5-2/6-8 = 3/-2 m of KL = 5-0/6-5 = 5 m of JL = 2-0/ 8-5 = 2/3
In order for two lines to be perpendicular, their slopes must be opposite reciprocals... FK is perpendicular to FL FK is perpendicular to KJ JL is perpendicular to FL JL is perpendicular to KJ FJ is perpendicular to KL