Final Answer:
The theorem or postulate that can be used to prove

Step-by-step explanation:
According to the
postulate, 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.
In this case, if angle
is congruent to angle
, angle
is congruent to angle
, and side
is common to both triangles, then we can apply the
postulate to establish the congruence of
and

This proof relies on the geometric properties of angles and sides within the triangles, demonstrating that they have corresponding parts that are congruent.