One of these triangles is the image of the other triangle after dilation.
What are the coordinates of the center of dilation?
What is the scale factor?
From smaller to larger, the scale factor is 4. Just take the ratio of the sides, (which you can find with the Pythagorean Theorem) and that fraction will give you the scale factor. I don't know the official way to do it, but go to a graphing website, plot these points, then draw lines connecting all similar points, A to A', B to B' and so on. Where all the lines intersect is the dilation point. So, the dilation point is (7,-1).