| − | A '''line segment''' is a finite, unbroken portion of a [[line]]. (Lines extend infinitely in both directions.) Alternatively, a line segment can be thought of as "the set of all [[point]]s that lie on the line between two given points. The two given points are called the ''end points'' of the line segment." <ref>[http://strader.cehd.tamu.edu/Mathematics/Geometry/PolygonLesson/Details/line_segment.html Texas A&M]</ref> | + | A '''line segment''' is a finite, unbroken portion of a [[line]]. A line extends infinitely in both directions; a line segment does not extend infinitely in either direction. Instead, a line segment ends at two points, called the ''end points'' of the line segment. <ref>[http://strader.cehd.tamu.edu/Mathematics/Geometry/PolygonLesson/Details/line_segment.html Texas A&M]</ref> Alternatively, a line segment can be thought of as "the set of all [[point]]s that lie on the line between" its endpoints. |
| | + | For example, the real line extends through all the real numbers from negative infinity to positive infinity - it contains every real number. A line segment of the real line contains all real numbers between two certain points, such as all the real numbers between 4 and 5. Such a line segment is more commonly known as an interval, [a,b]. |