Education Technology

Got parallel lines with corresponding angles congruent? with Cabri Jr.

Published on 06/09/2008

Activity Overview

Construct parallel lines in Cabri Jr., and students label and check if all corresponding angles are congruent.

Before the Activity

Students need basic knowledge of selecting Cabri Jr. tools, Clear key, Alpha key to drag, etc.

During the Activity

On New screen in Cabri Jr. F2 draw a Line. F3 select Parallel tool. Select a point not on the first line and then the first line to create the parallel lines. F5 Hide/Show> select Object to hide the points on the parallel lines. F2 draw a transversal line across the parallel lines. F2 Point> select Intersection to create a point of intersection of each parallel line and the transversal. Have students create points (F2> Point or Point on) on each line to allow for measuring all eight angles. Labeling each point can be done using F5 Alph-Num tool. Be sure the point is ?shimmering? or selected when creating label. So, when drag hand is used later the label stays with its point. (To label points?F5 select Alph-Num when a point is selected the curser gets longer and has an extra horizontal bar near the bottom of the curser. Hit ENTER to type the label. After you have typed the desired green letter and label is complete, hit ENTER. Clear to exit Alph-Num.) F5 select Measure> Angle to measure each of the eight angles. Have students drag each displayed angle measurement near its angle. After all eight angles have been measured; use the Alpha hand to drag the transversal line or the points on the transversal line. The corresponding angles remain congruent.

After the Activity

Further discussion could include: 1. F5 Calculate the sum of Same-Side Interior angles. 2. Alternate Interior angles are congruent. 3. Use the Alpha hand to drag the transversal perpendicular to the parallel lines. Take a 1to10. A 1to10 is a way to monitor the understanding of a class. Ask the students to 2nd quit Cabri Jr (or any APP), and have only a black curser on the calculator. Ask a question about their understanding of parallel lines, transversals, and the angles created. Students place a 1 to 10 on their screen. 1 equals the need for further explanation, and 10 equals total understanding of the concept. Screen Capture in TI-Navigator. (Quick Poll can also be used for 1to10)