Final answer:
To show that triangles ABC and XYZ are congruent by the ASA Postulate, we need to prove that the side between the two known congruent angles in one triangle (AB) is congruent to the corresponding side in the other triangle (XY).
Step-by-step explanation:
To prove that two triangles are congruent by the Angle-Side-Angle (ASA) Postulate, we must show that two angles and the included side of one triangle are congruent to two angles and the included side of the other triangle. In the case of triangles ABC and XYZ, if we already know two pairs of corresponding angles are congruent, we would need to demonstrate that the side between those angles in triangle ABC is congruent to the corresponding side between the congruent angles in triangle XYZ. Without loss of generality, let's assume we know angle A is congruent to angle X and angle B is congruent to angle Y. To apply the ASA Postulate successfully, we must also show that side AB in triangle ABC is congruent to side XY in triangle XYZ.