Construct Perpendicular and Parallel Lines with GeoMaster
To construct perpendicular or parallel lines with GeoMaster on the TI-84 Plus graphing calculator, you have to start with an already constructed line, segment, ray, vector, or side of a polygon or triangle. To construct a line that is perpendicular or parallel to an already constructed line, segment, ray, vector, or side of a triangle or polygon, follow these steps:
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 select appears in the upper-right corner of the screen. The first screen illustrates that the Perpendicular tool was selected from the DRAW menu.
Use the arrow keys to move the cursor to the already constructed line, segment, ray, vector, or side of a triangle or polygon, and then press [ENTER].
A perpendicular or parallel line appears. In the next step, this line is moved to the location of your choice.
Use the arrow keys to move the cursor to the location on the screen where you want to construct the perpendicular or parallel line. Press [ENTER] to anchor this location.
The third screen illustrates this step when constructing a perpendicular line. Notice that the coordinates of the cursor location appear at the bottom of the screen and that your figure is drawn in dashed lines, indicating that the construction is not yet complete.
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 which 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 parallel or perpendicular line, 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 though 4. When you are finished using that tool, you deactivate it by pressing [CLEAR] or by selecting another menu item.