This question is asking which diagram shows a pair of alternate angles.

Alternate angles occur when two parallel lines are cut by a transversal, and the angles formed on opposite sides of the transversal but inside the parallel lines are called alternate interior angles. These angles are congruent.

Looking at the diagrams:

• The first diagram shows two lines intersecting, but this does not form alternate angles.
• The second diagram shows two parallel lines intersected by a transversal. The angles labeled "y" and "x" are alternate angles.
• The third diagram shows two non-parallel lines, so this does not form alternate angles.
• The fourth diagram shows parallel lines cut by a transversal, but the angles are not arranged as alternate angles.

So, the second diagram correctly shows a pair of alternate angles.

Let me know if you need more clarification or have any questions! Here are some follow-up questions:

1. How can we identify alternate exterior angles?
2. What are corresponding angles and how do they differ from alternate angles?
3. How do we use alternate angles to prove lines are parallel?
4. What is the difference between consecutive interior angles and alternate interior angles?
5. Can alternate angles be used in proofs of congruent triangles?

Tip: When dealing with alternate angles, always look for parallel lines and a transversal cutting through them. Alternate angles will always be on opposite sides of the transversal and inside the parallel lines.