Geometry

Question Analysis:
This question deals with overlapping triangles and the use of shared sides.
The main focus is the reflexive property in congruence proofs.

Key Concept Explanation:
The reflexive property tells us that any geometric object is congruent to itself, including shared sides.

Step-by-Step Solution:
When two triangles share a side, that side belongs to both.
Therefore, it is congruent to itself by definition.

Common Mistakes:
Overthinking or assuming additional steps are requir...