Students will already be familiar with many, many shapes, but they may not know the mathematical names. One simple way to start is to identify whether or not a shape is a polygon. A polygon is closed figure made up of at least three sides and angles. Triangles, quadrilaterals, pentagons, hexagons, etc. are all polygons. Polygons can be weird shapes, have convex and concave sides, and can have any number of sides. Any shape with curves or open ends is NOT a polygon.
In this activity, students will move shapes from a template into the appropriate columns on their own storyboard. Interactive whiteboards or projected computer screens make this an engaging class activity, but students can just as easily work individually or in pairs on a computer.
See also Polygonia and Roundsville for a short math story.
Polygons can be categorized by the number of sides (and therefore angles) they have:
*These shapes are not required by the Common Core, but it is nice to have the names handy if inquiring minds want to know.
(These instructions are completely customizable. After clicking "Copy Activity", update the instructions on the Edit Tab of the assignment.)
Student Instructions
Sort the shapes provided into either Polygon or Not a Polygon.
Engage students by challenging them to find real-life examples of polygons around the room. Clipboards and checklists make this activity interactive and fun as students identify and record shapes they spot in everyday objects.
Clarify what makes a shape a polygon: it must be closed, have straight sides, and at least three angles. Use clear visuals to show examples and non-examples so students know what to look for.
Walk around the room together and point out a few polygons before students begin searching independently. Think aloud to demonstrate your reasoning process.
Give each student a simple sheet to tally or draw the polygons they find. Encourage labeling (triangle, quadrilateral, etc.) to reinforce vocabulary.
Invite students to share interesting polygons they discovered. Discuss tricky examples together to deepen understanding and clarify misconceptions.
A polygon is a closed shape with at least three straight sides and angles. Examples include triangles, quadrilaterals, and pentagons. Any shape with curved lines or open ends is not a polygon.
Encourage students to look for closed shapes with only straight sides. Guide them to drag these shapes into the 'Polygon' column, and those with curves or open ends into the 'Not a Polygon' column. Interactive whiteboards or digital templates make this activity engaging.
Try sorting activities where students move shapes into 'Polygon' or 'Not a Polygon' groups, use story-based math resources like Polygonia, or have students draw and label shapes with different numbers of sides.
Polygons have only straight, connected sides and are closed shapes. Non-polygons have curves, open ends, or sides that don't fully connect, so they don't meet the polygon definition.
Use interactive technology like whiteboards, pair students for teamwork, add a story element (e.g., shapes from 'Polygonia'), or let students create their own shapes to sort, making the lesson hands-on and fun.