2. • If two angles and a non-included side of one
triangle are congruent to two angles and the
corresponding non-included side of a second
triangle, then the two triangles are congruent.
Angle-Angle-Side (AAS)
Congruence Theorem
If Angle
EFBC ≅
∆ABC ∆≅ DEF
Then
Side
Angle
∠A D≅ ∠
∠C F≅ ∠
3. Proof of AAS Congruence Theorem
Given: A D∠ ≅ ∠ , C F,∠ ≅ ∠
Prove: ∆ABC ∆≅ DEF
EFBC ≅
∠A D≅ ∠ , C F,∠ ≅ ∠
Given
∠B E≅ ∠ Third angles theorem
∆ABC ∆≅ DEF ASA Congruence Postulate
EFBC ≅
