Polygons

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Objective

For the student to categorize two-dimensional figures based on properties.

Big Idea

Lesson Author

Cathy Skinner

Scottsdale, AZ

Grade Level

Fifth grade

Subjects

Math

Geometry

Standards

5.G.B.3

Understand that attributes belonging to a category of two-dimensional figures also belong to all subcategories of that category. For example, all rectangles have four right angles and squares are rectangles, so all squares have four right angles.

5.G.B.4

Classify two-dimensional figures in a hierarchy based on properties.

Introduction

In this activity students will be working in a group of four to sort and classify plane polygon figures.

Exploration of Polygon Shapes

15 minutes

In this portion of the activity I am looking and listening to students using their geometry vocabulary of lines, shapes and angles. I walk around helping students flesh out their vocabulary of right angles, obtuse angles. One table is working on irregular shapes vs regular shapes. Another table is putting them in groups based on the numbers they found imprinted on them. I then ask them to see if those numbers mean anything related to the shapes. They found out they did.

Reflective Evaluation

5 minutes

Before I have my students reflect on the lesson I ask them to tell me what do they know about geometry - shapes, lines? I am prompting them to see if they will related their understanding to the activity.

The students who only talked about angles are at a basic level of understanding. The students who were organizing based on irregular and regular polygons were moving further ahead in their understanding. They had to use their understanding of angles first and then place the shape in the correct group.

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