Construct Lines, Segments, Rays, and Vectors on the TI-84 Plus

By C. C. Edwards

Because two points determine a line, segment, ray, or vector, the directions for creating these objects with GeoMaster on the TI-84 Plus graphing calculator are much the same. To construct such objects, follow these steps:

  1. Select the appropriate tool from the DRAW menu.

    To do this, press [WINDOW] if the Menu bar is visible at the bottom of the screen or [GRAPH][WINDOW] if it is not. Use


    to move the cursor to the tool you wish to use and press [ENTER] to select that tool. The tool you selected appears in the upper-right corner of the screen. The first image illustrates that the Ray tool was selected from the DRAW menu.


  2. Use the arrow keys to move the cursor to the location of the first point that determines your line, segment, ray, or vector. Press [ENTER] to establish this point.

    As you move the cursor, its coordinates are displayed at the bottom of the screen and the anchored point appears in the shape of a diamond, as illustrated in the second image.

    After pressing [ENTER] in this step, you can precisely locate the point by giving the calculator the coordinates of that point. You can also label the point.

  3. Use the arrow keys to move the cursor to the location of the second point that determines the object and press [ENTER] to anchor that point.

    The third image illustrates this step when constructing a ray. Notice that the ray appears as a dashed line. This indicates that the ray, although it appears on the screen, has not yet been housed in the memory of the calculator.

  4. Press [ENTER] or move the cursor away from the object.

    This is a crucial step. If it is not followed, then the last object you created may vanish when you ask GeoMaster to perform another operation. After doing this step, the figure that appeared as a dashed line after performing Step 3 appears as a solid line. This indicates that your construction is now housed in the memory of the calculator.

After constructing a line segment, ray, or vector, the GeoMaster tool you were using remains active until you deactivate it. So if you want to construct more objects of the same kind, just repeat Steps 2 through 4. When you are finished using the tool, you deactivate it by pressing [CLEAR] or by selecting another menu item.