1.ΔABC≅ΔDEF by the AAS Congruence
2. Not necessarily congruent
3.ΔGHI≅ΔJKL by the SSS Congruence
1) Congruent triangles have congruent angles and congruent legs. Examining the 1st picture, we have two triangles with two congruent angles and one congruent side.
Note that we have a case of Angle Angle Side since we have two angles and one side not included.
ΔABC≅ΔDEF by the AAS Congruence
2) The second case displays a case where we have two congruent angles and one side,
But note that since the included side is not marked as congruent in the other triangle (It's UW≅XY, not UW≅YZ) then this pair of triangles is not necessarily congruent.
If UW≅YZ then we'd have a case for congruence.
Not necessarily Congruent
3) In this last case, we have two triangles whose legs are congruent. According to this theorem:
"If three sides of one triangle are congruent to three sides of another triangle, then the triangles are congruent as well."
ΔGHI≅ΔJKL by the SSS Congruence
Hence, sorting out the answers we have:
1.ΔABC≅ΔDEF by the AAS Congruence
2. Not Necessarily Congruent
3.ΔGHI≅ΔJKL by the SSS Congruence