Students sort quadrilaterals and polygons using a Venn Diagram. One Venn diagram has the tiles Quadrilaterals and Polygons with right angles. The other Venn diagram does not have titles allowing the students to determine how the shapes should be sorted. This can be done individually or with a partner. After sorting all the shapes, partners or whole class can discuss why they placed each shape under the titles or what tiles they would add to the Venn diagram. Great way to add some critical thinking and cooperative learning to your lesson!