Move and Reshape Figures in Cabri Jr.

By C. C. Edwards

You can move and reshape figures in the Cabri Jr. geometry application for the TI-84 Plus. When you move an object, all other objects associated with that object will also undergo a change. The circle and line in the first picture are associated objects because the center of the circle is also one of the points defining the line.

So if you move only the line, as in the second picture, the center of the circle moves with it because it is on the line. But the point on the circumference of the circle remains fixed because it is not on the line. Because the center and point on the circumference determine the radius of the circle, the size of the circle changes when only the line is moved.


And if you move only the circle, as illustrated in the third picture, the slope of the line changes because one of the points defining the line (the point that is also the center of the circle) moves with the circle but the other point that defines the line stays fixed.

You can reshape figures by moving the points that define the figure. An obvious example is increasing or decreasing the length of a segment by moving one of its endpoints.

You can change the size of a circle by moving the point on its circumference that defines the radius — this is the point the calculator left on the circumference when you constructed the circle. And you can reshape a triangle, quadrilateral, or polygon by moving one of its vertices.

To move an object, follow these steps:

  1. Press [CLEAR] to deactivate all Cabri Jr. tools.

    When no tools are active, no picture appears in the upper-left corner.

  2. Use the arrow keys to move the cursor to the object you want to move and press [ALPHA] when that object begins to blink.

    The cursor changes to a hand, as illustrated in the second picture.

  3. Use the arrow keys to move the selected object and press [ENTER] to anchor the new location.

    The cursor changes to a hollow arrow and the object remains anchored in its new location.