Like the dot product, the cross product has a geometric interpretation: the vector returned by a cross product operation is always perpendicular to the vectors crossed. The magnitude of the resulting vector cross is given by: 
where 
is the angle between the two vectors.
is the angle between the two vectors. Excercise 3-10.
Determine the angle between the vectors 
and 
: 
and : 
, 
, and 
. Using these values we find the following for 
: 
.