To analyze this diagram and answer the question:

1. Select the transversal connecting ∠4 and ∠5: The transversal that intersects both ∠4 and ∠5 is line $d$.

2. Classify the relationship between ∠4 and ∠5:

   • Both angles, ∠4 and ∠5, are on opposite sides of the transversal $d$ and are between the parallel lines $a$ and $b$.
   • Thus, ∠4 and ∠5 are alternate interior angles.

Summary:

• Transversal: $d$
• Relationship: Alternate interior angles

Would you like further clarification on any part of the solution?

Related Questions:

1. What is the definition of alternate interior angles?
2. How can you prove that two angles are alternate interior angles?
3. What other angle relationships exist with transversals and parallel lines?
4. Can alternate interior angles ever be non-equal?
5. What is the difference between corresponding and alternate angles?

Tip:

When parallel lines are cut by a transversal, alternate interior angles are always congruent.