Determine whether the line through each pair of points is perpendicular.
A(3, 9), B(7, 4) and C(-4, -13), D(1, -8)

A) not perpendicular
B) perpendicular

Question

Determine whether the line through each pair of points is perpendicular. ​
A(3, 9), B(7, 4) and C(-4, -13), D(1, -8)
​
A) not perpendicular
B) perpendicular

Quizplus · Accepted Answer

For the first pair of points, slope m1 = (4 - 9)/(7 - 3) = -5/4
For the second pair of points, slope m2 = (-8 + 13)/(1 + 4) = 5/5 = 1

Since the product of the slopes is not -1, the two lines are not perpendicular.

Determine Whether the Line Through Each Pair of Points Is