A three dimensional analogue of this is called the triple product:
. Before the graphical interpretation
is explained, it is worth noting that there is only one way to correctly
compute this quantity. We must take the cross product first, since the cross
product produces a vector which we can then dot with
. If we tried
to compute the dot product first, we would be left with trying to compute the
cross product of a vector and a scalar, which is an undefined operation.
From the picture, it is clear that the area vector of the base of the
parallelepiped is . Since this vector forms an angle
with the thrid vector, the volume of the figure is simply the base
times the perpendicular height,
.
This is the result of the triple product which can also be written in matrix notation as