Topic: Determining the angles between transversal and parallel lines.

Learning Objectives:

  1. Students will identify the relationship between angles formed by two parallel lines and a non-perpendicular transversal.
  2. Students will be able to use theorems and postulates to determine the congruence and values of angles formed by two parallel lines and a non-perpendicular transversal.
  3. Students will use algebra and solve equations to find the measure of angles from the transversal.
  4. Students will be able to convey their reasoning orally and in writting.

Common Core State Standards:


Understand congruence and similarity using physical models, transparencies, or geometry software.

  1. Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.

Key Vocab:

1.Corresponding Angles Postulate

  1. Alternate Exterior Angles Theorem
  2. Alternate Interior Angles Theorem
  3. Consecutive Interior Angles Theorem
  4. Consecutive Exterior Angles Theorem
  5. Vertical Angles Theorem

Prior Knowledge:

  1. Angle Relationships such as complementary, supplementary, adjacent, vertical, alternate interior, alternate exterior, corresponding, consecutive interior, and consecutive exterior.
  2. Solving one variable equations


Do now (5 mins to complete and 5 mins to go over): Identify the given angle relationships

Mini Lesson (20 – 25 mins): Describe all theorems and postulates with examples.

Activity (20 – 25 mins): Worksheet with problems progressing from easy to difficult that requires students to solve for the unknown angles when parallel lines are cut by a transversal. Students must give reasoning behind why they can say the value is equal to what they say it is (identify Theorems and Postulates present).

Exit ticket: Hand in activity worksheet.

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