Intro to Polygons Lesson

Sometimes I need to remember KISS - Keep It Simple Stupid.  I was introducing Polygons in 9th/10th Geometry class.  I was hoping they came in with some vocabulary and understanding.  I had them right up at the boards for three simple drawings to check for understanding.  It led to great discussions.

Board Problems

We discussed "perfect looking" hexagons vs not for the vocab word of regular.
I asked them to draw diagonals and then had them define a diagonal.
We noticed the number of triangles inside the polygon and saw the pattern to make the formula.
I finished with asking them to draw and name all the polygons they knew.  More great discussions...
Is a circle a polygon?  I had not defined it, so I asked them to and they got all 3 characteristics.
What about a square, rectangle, rhombus, and kite  - are they polygons?
One group came up with dodecagon but asked about how many sides a dodecahedron had so we discussed 2D vs 3D.
Edited to add one girl thought one of them was a "rhododendron"  Too cute.


Then, we came back to our desks for a Desmos card sort to clarify more vocabulary. Which led to more discussion.  I love when the card sorts ask for more than one way to sort things.  Genius!

Finally, a practice worksheet to put it all together.

I had the following meme on my daily agenda.  I guess this has turned into my High5.  Kids look forward to coming to class to see the meme and then it takes a minute but there is usually a smile or a laugh.  A great way to start each class.

Today's - being from Boston - we always sing "Sweet Caroline" at the Red Sox games:


It was a nice lesson for a Monday.  Thought I would share.