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Videos, worksheets, games and activities to help Geometry students learn triangle congruence by angle-side-angle (ASA) and angle-angle-side (AAS).

ASA and AAS

If two triangles are congruent, all three corresponding sides are congruent and all three corresponding angles are congruent. If two pairs of corresponding angles and the side between them are known to be congruent, the triangles are congruent. This shortcut is known as angle-side-angle (ASA). Another shortcut is angle-angle-side (AAS), where two pairs of angles and the non-included side are known to be congruent. ASA and AAS are important when solving proofs.

How to use the ASA and AAS shortcuts to determine the congruence of two triangles.

Triangle Congruence - SSS, SAS, ASA and AAS

Angle Side Angle Postulate

It two angles and the included side of one triangle are congruent to two angles and the included side of another triangle, then the two triangles are congruent.

Angle Angle Side Theorem

It two angles and a non-included side of one triangle are congruent to two angles and a non-included side of another triangle, then the two triangles are congruent.

This video shows you how to create a proof to show that two triangles which have two matching angles and one matching include side, are congruent.

If two angles and the included side of one triangle are congruent to two angles and the included side of another triangle, then the two triangles are congruent.

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