Khan Academy
Khan Academy: Recognizing Shapes
Discusses how to identify basic 2D shapes by their properties. [6:08]
Khan Academy
Khan Academy: Cousin Fal's Shape Collection
Looks at a collection of 2D shapes and discusses how to identify them based on their properties. [4:19]
CK-12 Foundation
Ck 12: Elem Math: Overview of Rectangles Squares Circles and Triangles
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on various two dimensional shapes including rectangles, squares, circles and triangles.