CK-12 Foundation
Ck 12: Elem Math: Overview of Area of Squares and Rectangles Word Problems
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on how to find the area of a square and rectangle.
Khan Academy
Khan Academy: Classifying Shapes by Line and Angle Types
Explains how to classify 2D shapes based on the properties of their sides and angles. [2:15]
Khan Academy
Khan Academy: Composing Shapes
Shows how shapes can be put together to make new shapes. [2:04]