Education Technology

# Activities

• ##### Subject Area

• Math: Geometry: Circles

9-12

30 Minutes

• ##### Device
• TI-83 Plus Family
• TI-84 Plus
• TI-84 Plus Silver Edition
• ##### Other Materials
Student Activity Page

## Cabri Jr. Inscribed and Central Angles

#### Activity Overview

This activity uses Cabri™ Jr. to explore the relationship between inscribed and central angles subtended from the same arc of a circle.

#### Before the Activity

Students require Activity Page

#### During the Activity

1. Draw a circle in the center of the screen. Label the center O.

• Use the point tool to make three points on the circle. Label the points A, B, and C as in Figure 1a.
• Construct angle BAC using the Segment tool.
• Construct angle BOC using the Segment tool. See Figure 1b.
• 2. Measure the two angles and using the Angle tool. Record the measurements in the table.
• Drag point B along the circle.
• Record the new angle measurements in the table.
• Continue to drag point B along the circle and record the measurements of the new angles formed.
• 3. Make a conjecture about the relationship between the measure of an inscribed angle and the central angle subtended by the same arc.

#### After the Activity

Students complete practice questions on activity page.