Education Technology

Angles in Circles

Published on 06/09/2008

Activity Overview

The student will use the Cabri Jr. APP to discover the relationship between inscribed and central angles in a circle.

Before the Activity

The students will have already constructed circles and angles using the Cabri Jr App.

During the Activity

The directions and justification for this activity are included in the attached document. Using Cabri, Jr. the students will construct circle with a central angle and an inscribed angle subtended by the same arc of the circle. They will measure each angle and then move one endpoint of the arc around the circle while recording the angle measures. They will then dilate the circle and complete the second chart. They will then compare the information to make a conjecture.

After the Activity

There will be a discussion as to whether this activity may be considered a proof because of the multiple results by the students in the class or is it still only a conjecture. We will then take the quiz which is attached to the above document.