Looking at the graph, we can say that the center of dilation is at point I since this point doesn't change.
We need to find the ratio of the distances between the new and the old.
For the new side, let's choose H'(-1, 6) and I'(3, 8)
Using distance formula :
And for the old or original side H(-3, 5) and I(3, 8)
Take the ratio between the new and the original distances :
ANSWER :
The scale factor is 2/3 and the center of dilation is at I(3, 8)