Use the Coord. & Eq. Tool in Cabri Jr.
The Coord. & Eq. tool in the Appearance menu of Cabri Jr. on the TI-84 Plus is used to find the equation of an already constructed line or circle or to find the coordinates of a point appearing on the screen.
To find the equation of a line or circle or the coordinates of a point, follow these steps:
Press [GRAPH] to select the Appearance menu. Use the
keys to place the cursor on the Coord. & Eq. option and press [ENTER] to select that option.
A symbol of the Coord. & Eq. tool appears in the upper-left corner of the screen.
Use the arrow keys to move the cursor to the object whose equation or coordinates you want to find and press [ENTER].
The object blinks when the cursor is placed on it. After pressing [ENTER], the equation or coordinates appear at the location of the cursor.
Use the arrow keys to move the equation or coordinates to a better location and press [ENTER] to anchor that location.
Repeat Steps 2 and 3 to find the equation of another line or circle or the coordinates of another point. When you are finished finding equations and coordinates, press [CLEAR] or select another menu item.
After you have found the equation of a line or circle or the coordinates of a point, you can move the object and watch the equation or coordinates change accordingly. This is illustrated in the third picture, where the line is moved.