Congruent Segments (Quick Exploration)

The following applet illustrates what it means for segments to be classified as congruent segments.   Interact with the applet below for a few minutes.  Be sure to move the locations of the black points around each time before you drag the slider!   Then answer the questions that follow.  
Questions:   1) What transformations have we learned about thus far?  List them. 2) What transformations did you observe here while interacting with this applet above?   3) How would you describe what it means for segments to be classified as congruent     segments with respect to any one (or more) of the transformations you observed here      in this applet?  Explain.