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.
CK-12 Foundation
Ck 12: Elem Math: Overview of Lines Curves Vertices and Sides of 2 D Shapes
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview on lines, curves and vertices of two dimensional shapes.
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 the properties of rectangles, squares, circles and triangles.
Khan Academy
Khan Academy: Hexaflexagons: Hexaflexagons 2
This video is based on, and in honor of, Martin Gardner's column from 1956, "Hexaflexagons," which can be found here: http://maa.org/pubs/focus/Gardner_Hexaflexagons12_1956.pdf. For more information, see the top comment below.
Khan Academy
Khan Academy: Correction to Total Final Velocity for Projectile
Correction to Total Final Velocity for Projectile Video found here: https://www.khanacademy.org/science/physics/two-dimensional-motion/two-dimensional-projectile-mot/v/total-final-velocity-for-projectile. [2:40]
PBS
Pbs: Odd Squad: Mr. Frank's Flat Cart
Learn about the relationships between two- and three-dimensional objects with the Odd Squad. A new villain is on the loose, and he's flattening things around town. Olive and Otto are on the case!