How to Identify Line Segments
- 1). Find the "points" at the end of the line segment you wish to identify. A line segment always falls between two points. Even if it crosses a third point in between, these "bounds" are always the ones that will define or "name" the line.
- 2). Write the names of the points next to one another. In abstract space, points are given letter names; therefore, write AB, or whichever letters correspond to the points. If you are working on a number line, or a Cartesian plane, skip to Step 4.
- 3). Draw a short, straight line over the letters to denote a line "segment." This will be read, "the line segment bounded by point A and point B," or simply, "segment A-B." You have identified this segment, and you do not need the following steps.
- 4). Check to see whether the line includes the points. If your line segment falls on a number line or Cartesian plane, its distance can be measured in discrete units. Some lines include the points they are bounded by, which is indicated by a darkened circle at the point in question, while others exclude them, which is indicated by an open circle.
- 5). Identify these segments by the coordinates of the points that bound them. If a line goes from -2 to 2, inclusive, on a number line, then the coordinates are -2 and 2. On a Cartesian plane, the coordinates have two parts: horizontal and vertical. These points may be written "(-2, 2)" and "(2, 3)."
- 6). Identify the segment using "greater than" and "less than" signs. If the line segment lies between -2 and 2, exclusive, you can write "-2 < 2." To indicate that the segment is inclusive, you must use a "greater than or equal to" sign, by drawing a line under the "<." If one end (-2) is included and not the other (2), the simplest way to identify the line segment is _> -2 and < 2.
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