If a figure does not touch or lie over the origin, each corresponding point will always move away from the origin after dilation.
A concave mirror can converge parallel beams of light at one point. But rays originating from the focus after reflection does not always travel parallel to the principal axis.
If Point A' (3, 6) is the image of Point A(1, 2) under a dilation with respect to the origin, what is the constant of dilation?