The vectors are
.
Cross product of the vectors
is determined as,

Cross product of the vectors
is


The vector
is orthogonal to
and
then their dot product is zero.
Consider
and 
Find the dot product of above two vectors.
\
is orthogonal to the vector
.
Consider
and
.
Find the dot product of above two vectors.
\
is orthogonal to the vector
.
is orthogonal to the both the vectors
and
.
Cross product of the vectors
is
.
orthogonal to the both the vectors
and
.