Shodor Education Foundation
Shodor Interactivate: Lesson: An Introduction to Quadrilaterals
Quadrilaterals-parallelograms, rectangles, and trapezoids-are thoroughly introduced in this lesson plan for upper elementary and middle school learners. Lots of resources are linked to it to help support the teacher and students....
Khan Academy
Khan Academy: Identifying Quadrilaterals
Learn about the properties of rectangles, rhombuses, and squares, and practice identifying them. Includes hints for questions. CCSS.Math.Content.3.G.A.1 Understand that shapes in different categories