How to Determine If Three Points Are Collinear on the TI-84 Plus
Three points are collinear if they are on the same line. GeoMaster on the TI-84 Plus graphing calculator can determine whether lines are parallel or perpendicular for you. It is sometimes difficult to determine if three points are collinear by just looking at the screen.
To determine if three points are collinear, follow these steps:
Select the Collinear? tool from the MISC menu.
To do this, press [GRAPH][GRAPH], use the arrow keys to move the cursor to the Collinear? tool, and press [ENTER]. The tool you selected appears in the upper-right corner of the screen.
Use the arrow keys to move the cursor to the first point and press [ENTER]. Move the cursor to the second point and press [ENTER]. Then move the cursor to the third point and press [ENTER]. The conclusion as to whether or not the points are collinear appears on the screen.
The selected points appear as diamonds where the points A, B, and C are selected. The word false appearing on the screen in this picture indicates that the points are not collinear.
If you want to determine if three other points are collinear, press [CLEAR] and then repeat Step 2.
The word true appearing on the screen indicates that the points D, B, and E are collinear.
When you are finished using the Collinear? tool, deactivate it by pressing [CLEAR] two times or by selecting another menu item.