Answer:
See below
Explanation:
Centre of dilation
Dilation gives you a new shape that is either larger or smaller than the original.
In either case, every ray that passes through corresponding points of the two shapes will converge at the centre of dilation (Point O in the diagram).
Scale factor
To get the scale factor, you measure the ratio of lengths of corresponding sides in the shapes.
For example, a line in the red figure below may be four times as long as the corresponding line in the other.
If the dilation converts the blue shape into the red one, the scale factor is 4:1.
If the dilation converts the red shape into the blue one, the scale factor is 1:4.