Ms. Chan's Geometry Honors Chat Room

Friday, February 24, 2012

Constructing the Orthocenters and Centroids of Triangles

I know that I didn't get to do this in class today but I am going to assign it anyway because there are directions on og 332 on how to construct an altitude of a triangle as well as a median of a triangle. If you have trouble following the directions, go to Youtube and do a search on how to construct the median of a triangle and how to construct the altitude of a triangle. There are numerous videos out there. I know. I've done the search myself.

orthocenter:


  • point of concurrency

  • 3 altitudes of a triangle

circumcenter



  • point of concurrency

  • 3 medians of a triangle

Follow the instructions on pg 332 to complete the following:

Construct:



  1. the orthocenter of an acute scalene triangle


  2. the orthocenter of an obtuse triangle


  3. the orthocenter of a right triangle


  4. the centroid of acute scalene triangle


  5. the centroid of of an obtuse triangle


  6. the centroid of a right triangle


  7. circumscribe a circle about an acute triangle


  8. circumscribe a circle about an obtuse triangle


  9. inscribe a circle in an acute triangle (remember, you MUST construct a perpendicular from the incenter to any side (preferably the longest side) of a triangle first BEFORE you can inscribe a circle!!!!)


  10. inscribe a circle in an obtuse triangle

Constructing the Circumcenters and Incenters of different types of triangles

Construct the:




  1. circumcenter of an acute triangle; then circumscribe a circle about the triangle


  2. circumcenter of an obtuse triangle; then circumscribe a circle about the triangle


  3. circumcenter of a right triangle; then circumscribe a circle about the triangle


  4. incenter of an acute triangle; then inscribe a circle in the triangle (don't forget to construct a perpendicular to the longest side of the triangle first!)


  5. incenter of an obtuse triangle; inscribe a circle


  6. incenter of a right triangle; inscribe a circle



if you are even the tiniest bit off, do it over again!!!!!! PERFECTION is what you are striving for in a construction!!!!




please use colored pencils and/or highlighters to help you identify the different perpendicular bisectors and angle bisectors in your constructions. no color = no bueno =(

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