Types of Polygons

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Objective

Students will be able to classify two-dimensional using one attribute.

Big Idea

Poly Polygons!

Opener

10 minutes

The beginning of this lesson is meant to create a little intrigue in the minds of the students as they draw upon their geometry knowledge thus far.  Using the document camera I show a portion of a polygon. 

Can you guess which shape I have?  (It’s pretty difficult when you can only see part of it.)

I ask the students to talk to their neighbor and make a prediction as to what shape the whole polygon will be.  After a minute or so I get the students to end their conversations by simply announcing loudly “bring it back.”  I use these three magic words daily in my instruction as a signal for students to end their conversations and put their attention back on me. 

Then I have students share some of their predictions.  If the student did not include a why in their response I use a prompting question to get more information from them.  i.e. “what evidence do you have to support that prediction.”  One of the focuses of Common Core is for students to be able to explain their thinking.  By constantly reminding students that they need a why with a response I can come closer to aligning their thinking to the new generation of standards. 

I repeat this polygon slow reveal for several shapes and listen as the students think deeper into every new reveal.

Practice

20 minutes

The main portion of this lesson will focus on building an understanding of how to classify shapes based on their attributes.  Classifying is somewhat of a higher level task that students are not very familiar with.  In the standard 5.G.4 students will have to classify shapes based on multiple attributes so in this lesson I have students start by sorting based on one attribute. 

I provide each group of students with a copy of the polygons required for the sort which I found on the Illuminations website as part of an activity called Sorting Polygons.  I copy the polygons on cardstock for each group because the shapes will be used in future lessons.  I have the students cut out the shapes to prepare for the activity. 

I also provide students with a copy of a one circle map.  This type of graphic organizer will be used in this lesson to sort shapes based on one attribute.

Once students have the shapes cut out we begin the activity.

Alright, today we are going to be classifying shapes based on their attributes.  Today we are going to look to divide shapes into two categories.  I will give you an attribute and you will put the shapes into two groups.  The shapes that have the attribute will go inside the circle and the shapes that do not have the attribute will go outside of the circle.

 I will display the attribute on the board and then you and your group will discuss the attribute and decide which shapes qualify and go in the circle, and which shapes do not qualify which go outside the circle.

I go through a variety of simple attributes one by one.  The attributes I choose from come from the Illuminations activity and a copy is provided in the resources.  For each attribute I give groups a few minutes to decide where the shapes should be placed on their graphic organizer as they discuss with their peers.  We then discuss each solution as a class and focus on correcting misconceptions.

Closer

15 minutes

To wrap up this activity I have students complete a quick exit slip.  I provide them with a half sheet of paper to write their response to the question I display on the board. 

Draw and label three shapes that have at least one right angle as an attribute.