Net of a Cone — free printable diagram

What the net of a cone looks like

A net is a 3D shape opened out flat, so that folding it back up rebuilds the solid. The net of a cone is one circle for the base and one sector of a larger circle for the slanted surface. A cone has a curved surface, which is why its net does not look like a set of flat polygons the way a cube's does.

Solid

Cone

Net is made of

one circle for the base and one sector of a larger circle for the slanted surface

Surfaces

1 flat circular surface + 1 curved surface

Is it a polyhedron?

No — it has a curved surface

• The sector curls round so that its straight edges meet, forming the point at the top. The curved edge of the sector becomes the rim of the base circle, so the two have to be the same length.
• The radius of the sector is the cone's slant height, not its vertical height — those are two different measurements, and mixing them up is the usual source of a wrong answer.
• A cone is not a polyhedron, so Euler's formula does not apply, and the number of faces it is said to have depends on whether your curriculum counts the curved surface as one.
• The area of the net is the surface area of the solid: πr² for the base plus πrl for the sector, where l is the slant height.