To find the scale factor , we need to pick pu a point and its dilated point. Let's take H and H' . Coordinate of H is (2,6) and of H' is (1,3) . And as we see that the coordinate of H' is half of the coordinate of H, that is 1 is half of 2 and 3 is half of 6. So the dilation factor is 1/2 . We can say that the dilation factor represents by what factor a coordinate change to its dilated coordinate .