\ \
If the initial point is
and the terminal point is
, then
the position vector is 
Area of the parallelogram :
\If u and v are adjacent sides of a parallelogram, then the area of the parallelogram is
.
The points are
and
.
The position vector is 
Substitute the points
and
in v.

Substitute the points
and
in v.

The vectors are
and 

The position vectors
and
are adjacent sides of a parallelogram.
The area of the parallelogram is 

The area of the parallelogram is 
The area of the parallelogram is 