By definition, Rotation is a transformation in which the figure is rotated about a point called "Center of rotation". The figure transformated (The Image) and the original figure (The Pre-Image) have:
1. Same shape.
2. Same size.
In this case you can observe in the picture that the figure ABC is the Pre-Image and the figure A'B'C' is the Image. The figure A'B'C' is obtained by rotating the original figure about a fixed point.
Since the shape and the size don't change, and the figure ABC was just turned, you can identify that the points A' B' and C' that correspond to A,B, and C are the folllowing: