 Triangle Congruence,
a selection of answers from the Dr. Math archives.
 Triangle Congruence
 I don't understand how to tell if two triangles are congruent.
 Congruence and Triangles
 Can you please explain how to determine, using SSS, SAS, and ASA,
how a shape is congruent or not?
 SSS, ASA, SAS Proofs
 I understand the ideas, but I'm not sure when and where to use them.
 SSA Theorem: Valid or Invalid?
 Why can't the SSA Theorem be used to prove congruence?
 SSA Proof
 Proving congruence using the SideSideAngle Theorem.
 SSA and Noncongruent Triangles
 Why can't you conclude that two triangles are congruent when
sidesideangle are congruent?
 AngleSideSide Does Not Work
 Can you give me a construction to show that AngleSideSide does not
prove two triangles congruent?
 Congruent Triangles  SSS Test
 How do you know if two triangles are congruent?
 Congruent and Similar Triangle Theorems
 Is there an AngleAngleAngle (AAA) triangle congruency theorem?
 Determining Triangle Similarity
 Given two triangles, how can you determine if they are similar?
 Congruent Parts Congruent Triangles
Congruent (CPCTC)
 When should we use CPCTC, and how does it prove anything?
 Theorem or Postulate?
 Shouldn't the three triangle postulates  SSS, ASA, and SAS  be theorems?
