From the given points, we may choose any three of then such and dind a two vector that express the sides of the parallelogram "or one side and a diagonal of the parallelogram", we may chose for example the points B, C, and D.
More over, we can choose point B to be the common point for the two sides "the initial point of the two vector", thus we need to find vector BD and vector BC, using equation as follows
\(BC \leq 5+1,2-3>\)
And, the other vector side BD is
\(BD \leq 3+1,-1-3>\)
\( \leq 4,-4>\)
And the cross product of both vectors is
\(BC\times BD \leq 6,-1>\times<4,-4>\)
Knowing, the cross product of the two vectors of the parallelogram we can use equation to find the area
Thus, the area of the parallelogram is 20 units squared.