Lesson 17

In previous grades, students describe a sequence of rigid transformations that exhibits the congruence between two figures. To prepare students for future congruence proofs, this lesson asks students to come up with a systematic, point-by-point sequence of transformations that will work to take any pair of congruent polygons onto one another. As the focus shifts to sequences of transformations between figures with more general characteristics rather than specific measurements, encourage students to explain how they know that their sequences will cause certain points or lines to coincide. When students consider how generalizable a strategy for defining sequences of rigid transformation is, they are looking for the structures of pairs of congruent figures (MP7).