Activity Overview
In this activity, students will construct angle bisectors and medians in quadrilaterals and explore the properties that appear to be true for four-sided figures. They may find it necessary to review the definitions and properties of special quadrilaterals in order to construct the figures.
Before the Activity
Install the Cabri Jr. App on the students' graphing calculators using TI Connect™, a TI Connectivity Cable and the Unit-to-Unit Link Cable
Use the TI-Navigator™ to transfer the attached Cabri Jr. AppVar files to each calculator
See the attached PDF file for detailed instructions for this activity
Print pages 155 - 158 from the attached PDF file for your class
During the Activity
Distribute the pages to your class.
Follow the Activity procedures:
Use the AppVar to go directly to the exploration section
Construct a parallelogram and its four angle bisector
Drag the vertex and /or side of the original parallelogram and observe the new quadrilateral formed by angle bisectors
Construct the medians of a generalized quadrilateral
Construct the quadrilateral formed by the medians
Drag the vertices and\or sides to form a special quadrilateral and note what happens to the quadrilateral formed by the medians
Calculate the ratio of the area of the original quadrilateral to the area of the quadrilateral formed by the medians
After the Activity
Review student results:
As a class, discuss questions that appeared to be more challenging
Re-teach concepts as necessary