Question

Line n passes through points (7, 12) and (4, 15). What is the slope of a line that is perpendicular to line n?

Answer 1

m = change in y/change in x

m = (12-15)/(7-4) = -3/3= -1

Perpendicular lines have slopes that multiply to -1.

If slope = 1/2 perpendicular = -2

In this case -1 perpendicular is 1.

Answer 2

slope of original = (15-12)/(4-7)
= 3/-3 = -1

slope of perpendicular = -1/-1 = 1