Skip to content
Exit presentation

Exploring Some Geometric Themes

Faces, edges and corners

A die has flat faces, straight edges and sharp corners. Count them on any solid, a shape with depth.

A cube: 6 faces, 8 corners, 12 edges.
Step 1 of 4
  1. A cube: 6 faces, 8 corners, 12 edges.
  2. One face — a flat piece.
  3. One edge — where two faces meet.
  4. One corner — where edges meet.

Rule: Count the flat faces. Count the edges, where two faces meet. Count the corners, also called vertices, where edges meet.

The table uses these shapes. A cuboid is a box with rectangle faces. A tetrahedron has 4 triangle faces. A prism has two matching flat ends. A pyramid comes to a point on top.

Five solids, with each count taken straight off the shape
SolidFacesCornersEdges
Cube6812
Cuboid6812
Triangular prism569
Square pyramid558
Tetrahedron446

A cube and a cuboid have the same counts. A square pyramid and a triangular prism both have 5 faces. The pyramid has 8 edges. The prism has 9.

Tap Count one more. Watch each part light up.

Loading lab…

Jump to lesson

This track

  1. 0 Start here
  2. 1 Faces, edges and corners
  3. 2 A flat plan that folds up
  4. 3 Six squares, and most plans do not fold
  5. 4 What you see from where
  6. 5 A relation hiding in the counts
  7. 6 A shape inside itself
  8. 7 What each stage really does
  9. 8 The carpet, and fractals around us
  10. 9 The big picture
  11. 10 Track quiz

Other tracks