Unit 6 · Similarity and Dilations

6.5SSS and SAS Triangle Similarity

Quick Answer

SSS Similarity: all three pairs of corresponding sides are proportional. SAS Similarity: two pairs of sides are proportional and the included angles are congruent.

Essential Question

How do SSS and SAS similarity differ from their congruence counterparts, and when would you choose one over the other?

Learning Goals

  • 1State the SSS Similarity Theorem.
  • 2State the SAS Similarity Theorem.
  • 3Apply SSS and SAS to determine if triangles are similar.
  • 4Choose the correct similarity criterion for a given problem.

Key Vocabulary

SSS Similarity Theorem

If all three pairs of corresponding sides of two triangles are proportional, the triangles are similar.

SAS Similarity Theorem

If two pairs of corresponding sides are proportional and the included angles are congruent, the triangles are similar.

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.