Lesson objective: Compute missing angles using angle relationships formed from transversals.

This lesson helps to build procedural skill with angle relationships. Task Cards (with visual representations of parallel lines and transversals) are used here because they support students as they reason with angles and angle measures they can deduce from a picture. Students are then able to create equations that represent congruent and supplementary angle relationships. This work develops students' understanding that parallel lines and transversals create angle relationships that can be used to determine other angles.

Students engage in Mathematical Practice 1 as they make sense of and persevere in angle relationship problems. Students will engage in productive struggle as the determine types of angle relationships, create equations that represent them, and recognize there are multiple pathways to find missing angles.

**Key vocabulary:**

- alternate interior angles
- alternate exterior angles
- corresponding angles
- parallel lines
- transversal

**Special materials needed:**

- Amazing Race checkpoint cards