Find the coordinates of the foot of perpendicular from the point (–1, 3) to the line 3x – 4y – 16 = 0.


Let the co-ordinates of the foot of the perpendicular from (-1, 3) to the line 3x – 4y – 16 = 0 be (a, b)


Let the slope of the line joining (-1, 3) and (a, b) be m1



Let the slope of the line 3x – 4y – 16 = 0 be m2




Since these two lines are perpendicular m1 × m2 = -1




3b – 9 = -4a – 4


4a + 3b = 5 …….(1)


Point (a, b) lies on the line 3x – 4y = 16


3a – 4b = 16 ……..(2)


Solving equations (1) and (2), we obtain


a = 68/25 and b = -49/25


Co-ordinates of the foot of perpendicular is (68/25, -49/25)


14
1