How to Reflect Geometric Objects in Cabri Jr.

By C. C. Edwards

Cabri Jr. for the TI-84 Plus calculator allows objects to be reflected in a line or a segment. When a geometric object is reflected in a line, that line acts like a mirror — hence the term “reflection.” The mirror image of the original object appears on the other side of the line.

To reflect an already constructed geometric object, follow these steps:

  1. Construct the line (or segment) of reflection.

    The first picture shows that the already constructed triangle is to be reflected in a line.


  2. Press [GRAPH] to access the F4 Transformation menu. Use


    to move the cursor to the Reflection option and press [ENTER] to select that option.

    A symbol of the tool appears in the upper-left corner of the screen.

  3. Use the arrow keys to place the cursor on the object to be reflected and press [ENTER] to select that object.

    Cabri Jr. can reflect only one object at a time. The object to be reflected blinks when the cursor is placed on it. When selecting a triangle or quadrilateral, all sides of the object must be blinking to select the whole object instead of just one side of the object. To do this, place the cursor inside the object and move it slightly until all sides are blinking.

  4. Use the arrow keys to move the cursor to the segment and press [ENTER].

    The reflection of the original object appears along with the original object.

  5. Repeat Steps 3 and 4 to reflect more objects. When you are finished reflecting objects, press [CLEAR] or select another menu item.

After reflecting objects, if you move the line (segment) of reflection, the reflected objects will move to the location defined by the new line or segment.