Visual examples of vertical angles in geometry, demonstrating pairs of opposite angles formed by intersecting lines.

Problem Description:

The task involves identifying pairs of angles that are vertical angles. Vertical angles are formed when two lines intersect, and they are the angles opposite each other at the intersection point. These angles are always congruent (equal in measure).

Solution Approach:

1. Identify Intersections: Look for points where two lines cross.
2. Locate Opposite Angles: At each intersection, identify the angles that are directly opposite each other.
3. Label Pairs: Mark the pairs of vertical angles.

Analysis of Each Image:

#### Row 1:
- A: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- B: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- C: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2

#### Row 2:
- D: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- E: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- F: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2

#### Row 3:
- G: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- H: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- I: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2

#### Row 4:
- J: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- K: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- L: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2

#### Row 5:
- M: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- N: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2
- O: Two lines intersect, forming four angles. The vertical angles are:
- Pair 1: Angle 1 and Angle 2

Final Answer:

Each image shows a pair of vertical angles. The pairs are as follows:

- A: Angle 1 and Angle 2
- B: Angle 1 and Angle 2
- C: Angle 1 and Angle 2
- D: Angle 1 and Angle 2
- E: Angle 1 and Angle 2
- F: Angle 1 and Angle 2
- G: Angle 1 and Angle 2
- H: Angle 1 and Angle 2
- I: Angle 1 and Angle 2
- J: Angle 1 and Angle 2
- K: Angle 1 and Angle 2
- L: Angle 1 and Angle 2
- M: Angle 1 and Angle 2
- N: Angle 1 and Angle 2
- O: Angle 1 and Angle 2

Thus, the solution is:

\[
\boxed{\text{All pairs are vertical angles as identified above.}}
\]