Answer:
57.2 units^2
Step-by-step explanation:
The coordinates provided form a parallelogram, not a rectangle. See the attached image for a diagram of EFGH. The area of a parallelogram is given by:
Area = (Base) x (Height)
The attachment explains an approach of using right triangles to find the base and height of the parallelogram.
I'm not confident this was the best approach, so I hope someone would comment if a simpler solution is available.
