This activity is intended to supplement Geometry, Chapter 3, Lesson 2.
Problem 1 - Exploring Parallel Lines
In this activity, students will develop and strengthen their knowledge about the angles formed when parallel lines are cut by a transversal. The measurement tool helps them discover the relationships between and among the various angles in the figure. Students will draw parallel lines, draw a transversal, and explore angle relationships.
Press APPS. Move down to the CabriJr application and press ENTER. Press ENTER, or any key, to begin using the application.
Move down and to the left and press ENTER to mark one point on the line. Move to the right and press ENTER to mark the second point defining the line.
Now we will measure angles and explore angle relationships.
With the angle measuring tool active, measure some of the other angles formed—corresponding, alternate interior, alternate exterior...
Move each measurement to a convenient location. Press CLEAR to turn off the hand
Move the pointer to one of the points which defined the location of the transversal. Press ALPHA to activate the hand and move this point. Observe the angle measures as the position of the transversal changes.
Problem 2 - Extension
Move the transversal until one of the angles has “crossed over” and observe that you now have consecutive interior angles that are supplementary.
Measure the remaining angles and observe the relationships among the angle measures.
Load a background image of parallel lines but by a transversal with angles named. Instruct students to move their cursors to: the interior, the exterior, to an angle with a specific characteristic (congruent to a given angle, supplementary to a given angle, ...).