Find the missing coordinate if A, B, and C are collinear.

A = (-7, 15), B = (-6, 15), C = (19, y)

Question

Find the missing coordinate if A, B, and C are collinear.

A = (-7, 15), B = (-6, 15), C = (19, y)

debbieg · Answer

Well, I was about to tell you to use A and B to find the equation for the line, and then use that equation with x=19 to find the y coordinate for C.

But then I looked a little bit closer at your actual points. Look at A and B. Notice something about them?

something about their y-coordinates?

And what does that tell you about the line that contains them both? :)

anonymous · Answer

THANK YOU SO MUCH!!LOL I CANT BELIEVE I NEVER NOTICED THAT!

debbieg · Answer

Haha, I almost didn't either. :) but my line equation method WOULD work, in the general case. :)