Continue Key Concepts and Vocabulary

  1. Introduce students to the perpendicular bisector theorem and the definition of a point of concurrency.  
  2. Introduce students to the circumcenter of the triangle and how to circumscribe a triangle. Have the students find the circumcenter of a triangle and notice the three different locations of the circumcenter: inside (acute triangle); outside (obtuse triangle); and on the triangle (right triangle).  
  3. Introduce the angle bisector theorem and the point of concurrency, showing the incenter as well as the center of the circle that is inscribed in the triangle.  
  4. Have students confirm whether the point in the triangle is the incenter or not. Have them give reasoning (mathematical proof/reasoning).
  5. Prepare a quiz. You can use this visual quiz in which students identify triangle properties.

Tips and Tools

Use this Khan Academy video on understanding centroids and medians. (9 minutes)

Highlight Mathematical Practice 7, Look for and make use of structure.

If appropriate, use Khan Academy videos for visual instruction on triangles.

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