A 3D shape with all straight edges and flat faces is a polyhedron. Other 3D shapes with least one curved surface are not polyhedra. A 3D shape with regular polygonal faces, meeting at equal angles, is ...

The net of a 3D shape is what a shape looks like when opened into a 2D shape. The net can help to show the areas of each face that make up the surface area of a shape. The same units are needed for ...