Two-dimensional (2D) shapes are completely flat. They cannot be picked up. A polygon is a 2D shape with straight sides that meet at vertices. Polygons have names that show the number of sides they ...

length width depth 3D shapes have different properties to 2D shapes. Faces - A face is a flat surface on a 3D shape. Edges - An edge is where two faces meet. For example a cube has 12 edges.