Transformations such as reflections, rotations, and translations (which are known as 'rigid motions'), all move objects but maintain the congruence of the original figure.
Reflection: to flip
Rotation: to turn
Translation: to slide
The IXL.com assignment that corresponds to this lesson is:
8th Grade - R.1 Identify reflections, rotations, and translations
http://www.ixl.com/math/grade-8/identify-reflections-rotations-and-translations
The video below will show you examples of all three rigid motion transformations. Use this video to help you with the lesson as well as IXL online learning target R.1 Identify reflections, rotations, and translations.