Education Development Center
Tune in to Learning: Polygons and Perimeter
Explore different polygons and find their perimeter with this interactive lesson from T.V.411. Students see examples of polygons in everyday life and have immediate feedback to your responses to lesson questions.
Harvard University
Harvard Smithsonian: Everyday Classroom Tools
The focus of this series of lessons is to engage students in an exploration of the world around them. The emphasis is on inquiry as students learn about the earth, sun, light, shapes and more.