325,646 views
37 votes
37 votes
A(-1, 4), B(2, -5), M(-3, 2), N(3,0). A(-4, -8), B(4, -6), M(-3, 5), N-1, -3)are they parallel or perpendicular

User Quima
by
2.7k points

1 Answer

23 votes
23 votes

A = (-1, 4), B = (2, -5)

M = (-3, 2), N = (3, 0)

If AB and MN have the same slope, then they are parallel

If the product of the slope of AB and MN is -1, then AB and MN are perpendicular

Let us find their slope and decide they are what

The slope = change of y/change of x

Change of y = yB - yA = -5 - 4 = -9

Change of x = xB - xA = 2 - (-1) = 2 + 1 = 3

The slope of AB = -9/3 = -3

Let us do the same with M and N

Change of y = yN - yM = 0 - 2 = -2

Change of x = xN - xM = 3 - (-3) = 3 + 3 = 6

The slope of MN = -2/6 = -1/3

Since -3 not equal -1/3

AB and MN are not parallel

Since -3 * -1/3 = 1

User Dave Jensen
by
2.9k points