Tuesday, February 2, 2016

MTBoS Blogging Initiative: Week 4 - Teach My Lesson

I love Geometry:  especially a little further in the year when you have covered enough topics to make things FUN and INTERESTING.

Last year was the first year I taught this lesson and I blogged about it here.  The gist of it is a fictional merry-go-round that is brought to our school to have the carpentry shop repair and repaint. My superintendent came in and went along with me on this.  The kids were very into accurately calculating the area, amount of paint, and total cost of the hexagonal merry-go-round.

The only info they were given was that it was a regular hexagon and the side measure.

What was fun was the many different ways students came up with the length of the "apothem".

I never introduced that word and these students had never calculated the area of a regular polygon.  My goal was to ensure they had strategies that would work for them during the state test and I knew there was NO way any of them would remember one more area formula!!

Some used the Pythagorean theorem because they realized by angle measures the triangles were equilateral.  Some used special right triangles.  And at least two ended up using trig!!

Here are links to everything I used.  Not all kids got all documents.  I scaffolded as needed since I have a number of students on IEPs.

Student Sheet
Student Help Sheet
Unit Plan
Smartboard slides


  1. Tina, this is wicked cool. Bookmarked so I can find when I get to polygons in a couple of months. Thanks for sharing!!

    1. You're welcome....Just sharing the MTBoS love! Would love to hear of any "edits" you make to this lesson.

  2. What a fun project. I love the MAP resources. I noticed in your blog post and on the shared document, you don't list the side measure. Do you vary that per student group? Per class? (Or maybe not at all!)
    I wonder if you could talk the English teacher into helping with the "write up a proposal" part of the assignment. Almost like an informative essay, or maybe a formal letter.

    1. I didn't list the side measure because I wanted them to fill in information given by the superintendent. I also think I will change it up this year just in case someone is a repeat student or has a sibling who took my course last year! :)

      I love the idea of getting the ELA teachers to help with the write up. It was arduous last year! I used to teach writing, so I know what it should look like, but I just didn't have the time to make them do the revisions they needed to. I think I will talk to ELA staff and see if this fits in any of their writing assignments. Thx for the idea!

  3. I looked at the link you provided to last year's post. I notice that last year you told the students not to make assumptions, such as assuming that all the triangles are equilateral. I like this idea -- but I noticed that there was no way for them to conclude that the hexagon was regular without making assumptions. (This year you told them that the hexagon was regular, but not last year.)

    I know what you mean about that apothem formula. Many Geometry texts don't even give that formula. On the other hand, the apothem formula can be used to derive the area of a circle.

    I'm glad that this lesson was successful -- more so because I'm especially interested in Geometry lessons.

    Thanks for participating in the MTBoS!