## Unit 5: Congruence, Proof, and Construction

### Overview

*Throughout the unit, students explore rigid motions isometries (translations, reflections, and rotations) in order to develop an understanding about what it means for two objects to be congruent. They establish triangle congruence criteria, based on analyses of rigid motions and formal constructions. Students solve problems about triangles, quadrilaterals and other polygons. They apply reasoning to complete geometric constructions and explain why they work.*

**Developed By:** Debbie Seldomridge & Cynthia Burke

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## Pre-Unit Assessment

## Lesson 1

Geometry Vocabulary

## Lesson 2

Geometry Glossary

## Lesson 3

An Introduction to Transformations

## Lesson 4

Transformations Viewed Algebraically

## Lesson 5

Properties Preserved by Translations

## Lesson 6

Properties Preserved by Reflections

## Lesson 7

Properties Preserved by Rotations

## Lesson 8

Rigid versus Non-Rigid Motion

## Lesson 9

Triangle Congruence Shortcuts

## Lesson 10

Geometric Constructions (Part I)

## Lesson 11

Geometric Constructions (Part 2)

## Lesson 12

Geometric Constructions in a Circle

## Lesson 13

Capstone Performance Task