The correct answer is:
Mario has shown that the two triangles are congruent. Three transformations are not always necessary when moving 1 triangle on top of the other.
Explanation:
The SSS (Side-Side-Side) congruency theorem states that if three sides of one triangle are congruent to the three sides of another triangle, then the two triangles are congruent. The fact that Mario was able to translate triangle \( \triangle ABC \) to \( \triangle A'B'C' \) and then rotate it to overlap \( \triangle LMN \) suggests that the corresponding sides are indeed equal, confirming the congruence of the two triangles without needing a reflection.
It's important to note that while the specific sequence of transformations (translation, rotation, reflection) can provide insight into congruence, having just any combination of translation and rotation can also lead to congruence, especially if the triangles coincide exactly after those transformations. Thus, it's not necessary to perform all three transformations to verify the congruency of the triangles.