← Geometry
Math · Geometry · Unit 2

Unit 2: Congruence

Students prove that figures are congruent by reasoning about rigid transformations. They prove the Triangle Congruence Theorems (SSS, SAS, ASA), the Perpendicular Bisector Theorem, and several theorems about quadrilaterals.

Worksheets

Every sheet has an answer key. Free to print, no login.

Unit
📝 Worksheet ✅ Answer guide
Concept
📝 Worksheet ✅ Answer key
Practice
Set 1
📝 Worksheet ✅ Answer key
Set 2
📝 Worksheet ✅ Answer key
Advanced
Set 1
📝 Worksheet ✅ Answer key
Set 2
📝 Worksheet ✅ Answer key

What this unit covers

A Congruent Figures · 5 lessons
Goals
  • Comprehend and generate congruence statements that establish corresponding parts.
  • Justify whether or not figures are congruent by reasoning about rigid transformations.
Lessons
  1. Congruent Parts, Part 1
  2. Congruent Parts, Part 2
  3. Congruent Triangles, Part 1
  4. Congruent Triangles, Part 2
  5. Points, Segments, and Zigzags
B Triangle Congruence Theorems · 6 lessons
Goals
  • Identify situations where Side-Side-Side, Angle-Side-Angle, and Side-Angle-Side Triangle Congruence Theorems apply.
  • Use previously proven theorems about triangles to write new proofs.
Lessons
  1. Side-Angle-Side Triangle Congruence
  2. Angle-Side-Angle Triangle Congruence
  3. The Perpendicular Bisector Theorem
  4. Side-Side-Side Triangle Congruence
  5. Practicing Proofs
  6. Side-Side-Angle (Sometimes) Congruence (Optional)
C Proofs about Quadrilaterals · 3 lessons
Goals
  • Critique others’ justifications about quadrilaterals and constructions.
  • Use previously proven theorems to write new proofs about quadrilaterals.
Lessons
  1. Proofs about Quadrilaterals
  2. Proofs about Parallelograms
  3. Bisect It
D Let’s Put It to Work · 1 lesson
Lessons
  1. Congruence for Quadrilaterals
← Unit 1 See the whole map Unit 3 →

Adapted from the Illustrative Mathematics curriculum (v.360), licensed CC BY-NC 4.0. © Illustrative Mathematics.