1. **Problem Statement:** Define a line segment and explain its properties with a detailed description. 2. A **line segment** is a part of a line that is bounded by two distinct endpoints. It contains every point on the line between its endpoints. 3. Unlike a line, which extends infinitely in both directions, a line segment has a fixed length. 4. If the endpoints of the line segment are labeled as $A$ and $B$, the line segment is denoted as $\overline{AB}$. 5. The length of the line segment $\overline{AB}$ is the distance between points $A$ and $B$, which can be calculated using the distance formula if coordinates are known: $$\text{Length} = \sqrt{(x_B - x_A)^2 + (y_B - y_A)^2}$$ 6. A line segment is one-dimensional and straight, and it is the simplest geometric object connecting two points. 7. **Diagram Description:** Imagine two points $A$ and $B$ on a plane connected by a straight path. This path is the line segment $\overline{AB}$. 8. In summary, a line segment is a finite part of a line with two endpoints, having a measurable length and containing all points between those endpoints.