In this activity, students will explore the proportional relationships involved in multiple parallel lines being cut by transversals. These relationships are approached through exploration of a sail design problem, where students are to find the lengths of pieces of fabric along the edge of a sail which has a design utilizing parallel lines. An understanding of the "Side-Splitter Theorem" and its corollary will be developed via exploration.

Depending upon the comfort level of students with Cabri Jr., this activity may take anywhere from about 40 minutes to just over an hour. The activity is written for the beginner, many screen captures are shown to assist the student through the activity. If the activity is being used for experienced Cabri Jr. users, it may be helpful to edit the activity to make it more appropriate for such students. Please feel free to edit this activity to meet the needs of your students!

In this activity, students will explore the proportional relationships involved in multiple parallel lines being cut by transversals. Each student should be provided with a copy of the attached document.

Review student answers: