Lesson objective: Fluently describe and perform sequences of transformations in the coordinate plane.

This lesson helps to build fluency with sequences of transformations in the coordinate plane. A preimage *A* and a second image *A" *are used here because they lead students to think about which transformation (from a given list) will result in the desired image. This work develops students' understanding that a two-dimensional figure is congruent to another if we can describe a sequence of reflections, rotations, and translations on the first that produces the second.

Students engage in Mathematical Practice 7 (make use of structure) as they describe transformations in the coordinate plane using features of the plane. Students may use full verbal descriptions or shorter ones (e.g. arrow notation or abbreviated descriptions) to clarify how the figure changed, but all necessary information must be included in the descriptions.

**Key vocabulary:**

- center of rotation
- line of reflection
- reflect
- rotate
- translate

**Special materials needed:**

- patty paper (optional)
- transparency and wet- or dry-erase marker (optional alternative to the patty paper