Is the line that contains the points (-3, 7) and (9, -4) perpendicular to the line that contains the points (4, 3) and (-7, -9)?
A) No
B) Insufficient information
C) Yes

Question

Quizplus · Accepted Answer

First, find the slope of the line containing the points (-3, 7) and (9, -4):

slope = (y2 - y1)/(x2 - x1)
slope = (-4 - 7)/(9 - (-3))
slope = (-11)/(9 + 3)
slope = (-11)/12

The slope of this line is -11/12.

Now, find the slope of the line containing the points (4, 3) and (-7, -9):

slope = (y2 - y1)/(x2 - x1)
slope = (-9 - 3)/(-7 - 4)
slope = (-12)/(-11)
slope = 12/11

The slope of this line is 12/11.

If two lines are perpendicular, their slopes are negative reciprocals of each other. That means that if the slope of one line is m1, and the slope of the other line is m2, then m1 * m2 = -1.

In this case, (-11/12) * (12/11) = -1, so the two lines are perpendicular. Therefore, the answer is C) Yes.

Is the Line That Contains the Points (-3, 7) and (9