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Angle Angle Side Postulate

Proving Congruent Triangles with AAS

The Angle Angle Side postulate (often abbreviated as AAS) states that if two angles and the non-included side one triangle are congruent to two angles and the non-included angle of another triangle, then these two triangles are congruent.
Worksheet & Activity on the Angle Angle Side Postulate
Example of Angle Angle Side Proof (AAS)

Identify Angle Angle Side relationship

Identify which pair of triangles below does NOT illustrate an angle angle side (AAS) relationship.

Practice Proofs

Prove $$\triangle ABC \cong \triangle DEC$$

Prove $$\triangle ABC \cong \triangle DEF$$

Can you identify the error in the AAS proof below?

What is wrong with the proof below?