created 08/26/97; revised 08/13/00, 10/07/00, 07/25/03, 07/25/09, 01/17/15

The previous chapter discussed some uses of the dot product:

**Length:**dot product of vector with itself = length^{2}**Orthogonality:**dot product of two perpendicular vectors = 0

In the first case, the angle between the vector and itself is 0°. In the second case, the angle between the two vectors is 90°.

Does the angle between two vectors have something to do with the dot product?