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It was an exciting class period recently in my Geometry Honors class.  We switched to having our Honors Students buy TI-Nspire CX calculator this year.  There was some grumbling from parents - like what is this expensive new calculator going to be able to do better than the tried and true TI-83 or TI-84.  I patiently explained what I thought would be the advantages - like we can use the Geometry App, I can send the students documents using the TI-Navigator, and my personal favorite - there is color.

I have been working with the students recently on altitudes and medians.  We talked about the centroid and the orthocenter.  For some reason I like talking about the Euler line - it's just cool!  I usually have the students draw a triangle and we draw the medians.  I have them cut out the triangle and balance it on their pencil at the centroid.  They think that part is neat, but the measuring and drawing in the medians - it's painstaking...as embarrassing as it is is, there is always someone - even in honors math that doesn't use the ruler correctly, etc.

This year I decided - hey we have this cool new piece of technology, let's try doing this activity on the Nspire.  Needless to say, it took about 1/4 of the time.  The kids loved it.  They showed me some new ways to do things, and I was able to fill in lots of other information at the same time.  For example, I could show them how the medians ALWAYS intersect in the centroid by having them drag the vertices of the triangles.  And, I could convince them that sometimes the altitudes DO go outside the triangle - they could tell me when that happens (when the triangle is obtuse) instead of me having to draw several examples and hope they believed me.

Also, I used a great activity from Teachers Pay Teachers from Emily Allman.  She designed it as a performance task.  I really enjoyed using it.  Check it out Triangle Centers Performance Task.

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