How to Construct Perpendicular Bisectors with GeoMaster

By C. C. Edwards

In GeoMaster on the TI-84 Plus graphing calculator, a perpendicular bisector can be constructed to an already existing line, segment, ray, vector, or side of a polygon or triangle. To construct a perpendicular bisector, follow these steps:

  1. Select the Perp Bisector 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. Press


    to move the cursor to the bottom of the menu, press


    again to move the cursor to the Perp Bisector tool, and press [ENTER]. The tool you selected appears in the upper-right corner of the screen.

  2. Use the arrow keys to move the cursor to the already constructed line and press [ENTER].

    The perpendicular bisector appears as a solid line. This indicates that you are finished with the construction.

After constructing a perpendicular bisector, the Perp Bisector tool remains active until you deactivate it. So if you want to construct more perpendicular bisectors, just repeat Step 2. When you are finished using the tool, you deactivate it by pressing [CLEAR] or by selecting another menu item.