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Rotation

Nets

The net of a 3D shape is what it would look like if it was unfolded and laid flat. 

There are many types of nets for the different 3D shapes. 

For example, below are the eleven different ways of making a 3D cube from a 2D net.

A series of 11 black and white line diagrams showing the different ways of forming a 3D cube from a 2D net.
Cube Nets

A net is made from polygons (2D shapes with straight sides) that can be folded and joined to make a polyhedron (a 3D shape with polygon faces). 

Some examples of polyhedrons are cubes, cuboids and prisms. 

Black and white line diagrams of a 3D cube and cuboid. The cube has a pink square cross-section revealed inside it, and the cuboid an orange cross-section.
Cube and Cuboid (Polyhedrons)

Cones and spheres are not polyhedrons as their faces are not polygons – they are curved. 

A prism is any shape where its two opposite ends are equal shapes, called bases, and the sides in between these bases are parallelograms. Parallelograms are quadrilaterals with two pairs of parallel sides – so squares and rectangles are also parallelograms. You can see that this shape below is a prism, as its ends are equal shapes (triangles) and the other sides joining these ends are three rectangles. It would be called a triangle-based prism.  

 

A black line drawing of a triangular prism. The face of the prism is a right-angled triangle, and part way down the length of the shape is a green coloured cross-section, identical to the faces at both ends to indicate that the shape is a prism.
Triangular Prism

Prisms should have the same cross-section all the way along – meaning if they were cut at any point along their length, the shape revealed inside was exactly the same as the bases.  

 

A line diagram of a pentagonal prism with a slice of its cross section coloured in yellow. The cross-section is identical shape and size to the faces of the shape at each end, demonstrating that this is a prisms.
Prism Cross Section