created: 08/26/97; revised: 08/14/00, 07/26/03, 07/23/09, 01/18/15, 04/02/16

CHAPTER 10 — Angle between 3D Vectors

Length: Dot product of vector with itself&nbsp; = &nbsp;length 2
Perpendicularity: Dot product of perpendicular vectors&nbsp; = &nbsp;0
Angle: cos&theta;&nbsp; = &nbsp; dot product of two unit vectors

The dot product is used for:

This chapter adds nothing new, but extends the third application to the angle between vectors in 3D space.

What is the angle between two edges of a cardboard box that meet in a corner?