Published on 04/11/2006

#### Activity Overview

This activity uses Cabri™ Jr. to discover that the perpendicular of a chord passes through the centre of a circle.

#### Before the Activity

Students require the activity handout.

#### During the Activity

1. Draw a circle in the center of the screen. Label the center O. 2. Draw two points that are on the circle. Label the points A and B. Use the Segment tool to construct a chord, AB, connecting the two points.See Figure 1. 3. Construct a perpendicular bisector to AB. Use the Point Intersection tool to construct a point at the intersection of the chord and the perpendicular bisector. Label the point C. See Figure 3. 4. Grab point B and move it to a new location on the circle.

#### After the Activity

Go over answers to Student hand out. Reteach as necessary.