Congruent line segments with equal length of 12 units.

Problem Analysis:

The image shows two line segments, each labeled with a length of 12 units. The text below the image states "Congruent line segments." The task is to understand and explain why these line segments are congruent.

Solution Explanation:

#### Step 1: Definition of Congruent Line Segments
Two line segments are said to be congruent if they have the same length. In other words, congruent line segments are identical in size, regardless of their orientation or position.

#### Step 2: Observing the Given Line Segments
- The first line segment is horizontal and has a length of 12 units.
- The second line segment is slanted (not horizontal) and also has a length of 12 units.

Both line segments are explicitly labeled as having a length of 12 units.

#### Step 3: Comparing the Lengths
Since both line segments have the same length (12 units), they satisfy the condition for being congruent. The orientation (horizontal vs. slanted) does not affect their congruence because congruence only depends on the lengths of the segments, not their positions or orientations.

#### Step 4: Conclusion
Because the two line segments have identical lengths (12 units each), they are congruent by definition.

Final Answer:

\[
\boxed{\text{The line segments are congruent because they have the same length (12 units).}}
\]