# Geo.1 Constructions and Rigid Transformations

In this unit, students first informally explore geometric properties using straightedge and compass constructions. This allows them to build conjectures and observations before formally defining rotations, reflections, and translations. In middle school, students studied transformations of figures in the coordinate plane. In this unit, they transition to more formal definitions that don't rely on the coordinate plane, and the focus shifts from transforming whole figures towards a more point-by-point analysis. Students then begin to use the rigorous definitions they developed to prove statements involving angles and distances, preparing them for congruence proofs in the next unit.

A blank reference chart is provided for students, and a completed reference chart for teachers. The purpose of the reference chart is to be a resource for students to reference as they make formal arguments. Students will continue adding to it throughout the course. Refer to *About These Materials* in the Geometry course for more information.

### Lessons

#### Constructions

- 1Build It
- 2Constructing Patterns
- 3Construction Techniques 1: Perpendicular Bisectors
- 4Construction Techniques 2: Equilateral Triangles
- 5Construction Techniques 3: Perpendicular Lines and Angle Bisectors
- 6Construction Techniques 4: Parallel and Perpendicular Lines
- 7Construction Techniques 5: Squares
- 8Using Technology for Constructions
- 9Speedy Delivery