To determine which pair of triangles is similar, let's analyze the diagram and the given condition $BE \parallel CD$:

Steps to Solve:

1. Parallel Lines and Corresponding Angles:

   • Since $BE \parallel CD$ and $AC$ is a transversal, corresponding angles are equal.
     • $\angle ABE = \angle ACD$ (Corresponding Angles).
   • Similarly, since $BE \parallel CD$ and $AD$ is another transversal, corresponding angles:
     • $\angle AEB = \angle ADC$.

2. Triangles in the Diagram:

   • Triangles ABE and ACD share two pairs of equal angles:
     • $\angle ABE = \angle ACD$
     • $\angle AEB = \angle ADC$
   • By the AA (Angle-Angle) Similarity Criterion, triangles $\triangle ABE$ and $\triangle ACD$ are similar.

Correct Answer:

$\triangle ABE$ and $\triangle ACD$ (Option 3).

Would you like a deeper explanation or a diagram breakdown? Let me know!

Here are 5 related questions to expand your understanding:

1. How do you identify corresponding angles with parallel lines?
2. What are the similarity criteria for triangles (e.g., AA, SAS, SSS)?
3. How do you prove triangles are congruent instead of similar?
4. Can two triangles be similar but not congruent? Why?
5. How does the concept of transversal lines apply to real-world geometry?

Tip: When dealing with parallel lines, always look for transversal lines to identify corresponding, alternate interior, or alternate exterior angles.