A net is what a 3D shape looks like when completely unfolded and laid flat. Every face of the shape appears as a flat polygon in the net.
Folding the net back up along the edges recreates the 3D shape.
Nets are useful for calculating surface area — add up the area of every face shown in the net.
Many nets are possible for the same shape. A cube has 11 different valid nets.
Remember
A net is just a 3D shape with all its faces "peeled open" and laid flat. If you can fold it up into the shape, it's a valid net.
Real World
Cereal boxes and packaging are designed using nets. Before a box is folded, it's a flat sheet cut in the shape of a net.
Feeling ready?
Put this concept to work with a practice workout.