Unit 5 · Triangle Congruence and ProofProof-based

5.6Determining Whether Enough Information Is Given

Quick Answer

Check whether the given information matches one of the five valid shortcuts: SSS, SAS, ASA, AAS, or HL. If it matches SSA or AAA, there is not enough information to guarantee congruence.

Essential Question

How do we decide whether the information given in a problem is sufficient to prove two triangles congruent?

Learning Goals

  • 1Identify which congruence shortcut applies to given information.
  • 2Recognize when information is insufficient (SSA, AAA).
  • 3Use diagrams to extract implied information (shared sides, vertical angles).
  • 4Determine what additional information would be needed to prove congruence.

Key Vocabulary

AAA

Angle-Angle-Angle — NOT a congruence shortcut; proves similarity, not congruence.

SSA

Side-Side-Angle — NOT a valid congruence shortcut in general.

Reflexive Property

A segment or angle is congruent to itself; used to identify shared sides or angles.

Full lesson content coming soon

Worked examples, guided practice problems, a workbook, quiz, and downloadable PDF resources will be added to this lesson in Phase 2. The learning goals and vocabulary above reflect the complete lesson scope.