Let:
[tex]A=(x1,y1)[/tex]The coordinate of the missing point of the parallelogram
We can find the x-coordinate x1 as:
[tex]\begin{gathered} (2,9);(2,3);(3,0);(x1,y1) \\ since \\ 2=2 \\ x1=3 \end{gathered}[/tex]And for y1:
[tex]\begin{gathered} \Delta y_{\text{ }}of_{\text{ }}(2,3)_{\text{ }}and_{\text{ }}(3,0)\colon_{\text{ }}0-3=-3 \\ so\colon \\ y1=9-3=6 \end{gathered}[/tex]Therefore:
[tex]A=(3,6)[/tex]The parallelogram will be: