where is the angle between the vector and a vector normal to the plane of and (cf Fig. 8).

Thus, the absolute value of the triple scalar product is equal the volume of the box whose sides are given by the vectors , and .

For any three vectors
,
and
,
we have:

where , and with respect to an orthonormal direct basis.

Thus, the volume of the parallelepiped whose sides are given by , and is equal to 3.