Brainlag PlusFaces, edges and vertices of prisms and pyramids, the nets that fold into them, and how to read and draw a plan, a front elevation and a side elevation.
Faces, edges and vertices
A face is a flat surface, an edge is where two faces meet, and a vertex is a corner.
The plural of vertex is vertices.
- a prism on a shape with k sides: 2 ends + k rectangles = k + 2 faces
- edges: k on each end + k along the length = 3k
- vertices: k on each end = 2k
- a pyramid on a shape with k sides: k + 1 faces, 2k edges, k + 1 vertices
A quick check that works for all of these: faces + vertices − edges = 2. A cube has 6 faces, 8 vertices and 12 edges, and 6 + 8 − 12 = 2.
The rest of this lesson and its 7 practice questions are in Plus.
Screen 1 of 4, free to read.
- 7 exam-style questions, marked as you go, each with a worked solution
- Anything you get wrong is saved to your flashcards