3D solids and their parts
A 3D solid has length, width and height. Describe it by its faces, edges and vertices.
A 3D solid is a shape that takes up space — it has length, width and height. A ball, a box and an ice-cream cone are all 3D.
We describe a solid using three parts:
- A face is a flat surface of the solid.
- An edge is a line where two faces meet.
- A vertex is a corner where edges meet (the plural is vertices).
Some solids to recognise: a cube (6 square faces), a cuboid (6 rectangular faces), a cylinder (2 circular faces and one curved surface), a sphere (one curved surface), a cone and a pyramid.
A cuboid has 6 faces, 12 edges and 8 vertices. Counting these is a neat way to tell solids apart.
- A 3D solid has length, width and height.
- Face = flat surface; edge = line; vertex = corner.
- A cube has 6 square faces; a cuboid has 6 rectangular faces.
- A cuboid has 6 faces, 12 edges and 8 vertices.