The endpoints of line AB are A(9,4) and B(5,-4). The endpoints of its image after a dilation are A'(6,3) and B'(3,-3). Explain how to find the scale factor. I have confused myself... what is the formula I would use to explain how I got my answer

Question

The endpoints of line AB are A(9,4) and B(5,-4).  The endpoints of its image after a dilation are A'(6,3) and B'(3,-3).  Explain how to find the scale factor.   I have confused myself... what is the formula I would use to explain how I got my answer

anonymous · Answer

find the length of AB  and A'B' using distance formula 
and this will give u the artio of the lengths and hence the scale factor can be obtained by taking suitable ratio....

anonymous · Answer

The problem is that my friend told me the answer but I cant figure out the steps on how he got to it. Scale is 3/4.

anonymous · Answer

When I use the distance formula I get 1/2 instead of 3/4

anonymous · Answer

never mind I figured it out