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Angle-Angle-Side (AAS) Congruence Theorem
See It in Action
Two examples of the idea done right—and one common look-alike that is not right.
EXAMPLE
EXAMPLE
NON-EXAMPLE
Definition
The Angle-Angle-Side (AAS) Congruence Theorem states:
If two angles and a non-included side of one triangle are congruent to two angles and the corresponding non-included side of another triangle, then the two triangles are congruent.
Key points:
The side is not between the two angles (that would be ASA).
Once two pairs of angles are known to be congruent, the third angle must also be congruent (Triangle Sum Theorem), so effectively AAS is just another case of ASA.
Video
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