Points of Concurrency: Can We Concur on Triangles?

This is one lesson in a larger Unit Plan that addressess Traingular Relationships.  It has proofs, real world problems, constructions, a unit project, assessments, and more.  This lesson, “Can We Concur on Triangles? (Points of Concurrency)”, involves hands-on constructions with straight-edge and compass, patty paper, and/or a Mira, to draw perpendicular bisectors, altitudes, and medians, then find circumcenters, orthocenters, and centroids.  Resource includes a variety of downloadable files, including student handouts.  The entire unit plan can be found here. This lesson has a hands on activity to find the centroid of a triangle to start the lesson. Then there are worksheets to be used individually or in pairs to draw perpendicular bisectors, altitudes, and medians, then find circumcenters, orthocenters, and centroids. Different worksheets use either straight-edge and compass, patty paper, and/or a Mira. The teacher could easily use one or all of the activities.

Standards & Objectives

Essential and guiding questions: 

How can we use relationships found from angle bisectors, altitudes, medians, perpendicular bisectors in triangles?

 

Lesson Variations

Blooms taxonomy level: 
Understanding

Helpful Hints

Materials:

  • Computer (optional)
  • pencil
  • ruler
  • scissors
  • cardboard
  • poster board
  • compass
  • patty paper
  • worksheets
  • Miras

References

Contributors: