Question

ABCD is a rectangle on a coordinate grid with AB || CD and BC || AD. If the slope of AB is 2/7, what is the slope of BC?

Option A: - 7/2

Option B: - 2/7

Option C: 7/2

Option D: 2/7

Answer 1

remember that the product of slopes of lines at 90 degrees to each other is -1

Answer 2

we know that AB and BC are pependicular (prop. of rectangle).
and we also know that the product of slopes of a line and a perpendicular from it is -1.

m*n=-1
put 1 value you will get the other.