AAS Congruence Rule Angle-Angle-Side

Two triangles are congruent, if two pairs of corresponding angles and one pair of opposite sides are equal in both triangles.

In above figure there are two triangles, △CAB and △PQR 

△CAB and △PQR has two pairs of 

corresponding angles ∠A = ∠R, ∠C = ∠P and 

one pair of opposite sides side CB = side PQ.                  
are equal in both triangles.

Two pairs of corresponding angles and one pair of opposite sides are equal in both triangles.

∴ △CAB  ≅  △PQR by (AAS) congruent rule.

Symbol Congruent denoted by sign  ( ≅)