Question

How to find area of parallelogram with coordinates of verticles?

Answer 1

You find a parallelogram area by this formula:
$A=b\cdot h$
Where b is its base and h, its height.
You get b's value applying distance between two points formula.
If A and B points form the base:
$A(x_1,y_1)\;\;\;\;B(x_2,y_2) \\ \\ d_{AB}= \sqrt{(x_1-x_2)^2+(y_1-y_2)^2} =b$

And h is the perpendicular distance between both bases.
You can visit next link to know further about it:
https://www.ck12.org/geometry/Distance-Between-Parallel-Lines/lesson/Distance-Between-Parallel-Lines
-GEOM/

And in attached picture you can find an example in progress you may want to finish.