8.G.5 Reteaching
- Author:
- Haley Harrison-Jones
At the end of this lesson, students will be able to...
1: Formulate arguments to establish facts about the interior and exterior angles of a triangle
2: Formulate arguments about the angles created when parallel lines are cut by a transversal
Part 1
Explore the figure below by dragging movable points, and record at least 6 observations.
What are the six (or more) observations you made about the graphic above? Answer in a numbered list.
Part 2
Match types of angles to their properties
Part 3: Angles in Triangles
Task:
1. Explore the given triangle. Make at least 2 observations about the angles emphasized.
2. Use your observations to make a conjecture about the relationship between interior and exterior triangle angles.
3. Open a new GeoGebra Geometry worksheet. Build at least one triangle and use the tools to test your theory from question 2.
(Repeat steps 1-3 as needed)
4. Write a rule that is always true about the interior and exterior angles of a triangle. Share your rule and a screenshot of your work to the Padlet.
Share your work using a screenshot from Question 3 and your rule from Question 4 to this Padlet below.
Extension Activity
1. Prove the Triangle Exterior Angle Theorem algebraically.