This lesson goes with Section 2.6 of the Discovering Geometry textbook, but you could use it with any book.

Group Size: Any

Learning Objectives:

Students will be able to identify special angles on parallel lines and will discover and apply conjectures about these angle pairs.

Guiding Question:

When two parallel lines are cut by a transversal, how are the angles related?


Tracing paper is best cut into little squares is best. Patty paper is ok. Student copies of the investigation handout. Multimedia projector if you want to show the powerpoint presentation.


1). Begin with direct instruction on the vocabulary of:

  • Transversal
  • Corresponding Angles
  • Alternate Interior Angles
  • Alternate Exterior Angles
(Students might take down definitions of these terms in their notebook).

2). Then drill students on the angle pairs using the first 2 pages of the investigation.

3). Then let small groups work on the investigation. After most students have at least started the "corresponding angles" activity, show the powerpoint to demonstrate how they were supposed to solve it. If possible, first let a group describe how they successfully completed the corresponding angles activity, and then use the powerpoint to flesh out what they said.


Homework questions from the book.

Attached Files:



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