What is a polygon anyway? Use this flipchart to help kids explore polygons. Teachers can sort shapes into two groups, and then the kids can create their definitions of a polygon. After the definition has been created, there are two pages for practice. Students can come to the board and sort and/or vote in their answers. I know this activity turns up in several places, so I just made it into an interactive flipchart.
Polygon Flipchart by Kellum is licensed under a Creative Commons Attributi