This lesson introduces students to concepts and skills that they will use throughout the year. Students will learn that the terms point and line are considered "undefined." Students will play musical chairs while learning to develop precise definitions of circle, angle, parallel line, and perpendicular line, using counterexamples at different classroom stations. Students will identify models, use notation, and make sketches of these terms.

### General Information

**Subject(s):**Mathematics

**Grade Level(s):**9, 10

**Intended Audience:**Educators

**Suggested Technology:**Document Camera, Computer for Presenter, Interactive Whiteboard, Computer Media Player

**Instructional Time:**40 Minute(s)

**Keywords:**point, line, definitions, example, counterexample, geometry, , parallel line, perpendicular line, angle, circle, vocabulary, word structure

**Instructional Component Type(s):**

**Lesson Plan**

**Resource Collection:**

__FCR-STEMLearn Geometry__