Joe is performing a dilation. One of his points is Y'(-4, 2), and another point is Y(-2, 1). What scale factor is he using?

2
-1/2
1/2
1

Question

Joe is performing a dilation. One of his points is Y'(-4, 2), and another point is Y(-2, 1). What scale factor is he using?


2
-1/2
1/2
1

anonymous · Answer

It is not 1/2

hero · Answer

I forget which is the image and which is the pre-image. I think its 2

hero · Answer

If it's not 1/2, then it has to be 2.

anonymous · Answer

The pre-image is the original image
the image is the new image

directrix · Answer

I'm betting on 1:2 assuming Y' is the post image and y the pre-image.

hero · Answer

then that means Y is the original image and Y' is the dilated image. Directrix, you have it backwards.

directrix · Answer

-2/x = 1/2
x = -4
where x is the x-coordinate of the post-image or image

anonymous · Answer

I have alreaady tried 1/2 it is not right

directrix · Answer

Okay. I concur with Hero's 2 but I can't guarantee anything for myself.

directrix · Answer

It cannot be 1. If 1/2 is out, -1/2 is also out. That leaves 2.

anonymous · Answer

2 was right

hero · Answer

Where's my medal?

directrix · Answer

Your medal?

anonymous · Answer

There is your medal

hero · Answer

lol

directrix · Answer

@ Hero --> Check this. Based on my stumbling here, I think we know this answer. http://openstudy.com/study#/updates/4f4e4b7ee4b019d0ebae284a

anonymous · Answer

Ill give you one 2 Directrix

directrix · Answer

Thank you.