Question

If AB is perpendicular to CD, then determine the slope of AB when the slope of CD is -2

Answer 1

perpendicular lines have negative reciprocal slopes

do you know how to find the reciprocal of -2?

Answer 2

no

Answer 3

if we have a number, ex. A, we divide 1 by A to get the reciprocal

so, using that same logic, the reciprocal of -2 is -1/2

with me so far?

Answer 4

yes!

Answer 5

good, now, "negative reciprocal" just means we multiply the reciprocal by -1

so (-1/2) * (-1) = 1/2

and your answer is 1/2

Answer 6

okay

Answer 7

The slope of AB is 1/2. You can multiply -2 by -1 and flip 2/1 giving you 1/2, OR you can draw a graph

Answer 8

so the slope is

Answer 9

2/1?

Answer 10

@mathmate