Lesson objective: Understand and describe the results of transformations in the coordinate plane.

Students bring prior knowledge of transformations from 8.G.1. This prior knowledge is extended to descriptions of transformations in the coordinate plane as students use coordinates to describe transformations precisely and accurately. A conceptual challenge students may encounter is understanding points of rotation and lines of reflection.

The concept is developed through work with vertices of figures described by ordered pairs, which lead students to operate and perform their transformations in the coordinate plane.

This work helps students deepen their understanding of operations because describing transformations may require describing operations on coordinate pairs.

Students engage in Mathematical Practice 4 (model with mathematics) as they use coordinates and transformation to reposition and reorient kites shown on a coordinate plane. Tracing figures on patty paper or a transparency might be helpful for completing the task.

**Key vocabulary:**

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

**Special materials needed:**

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