A GRE question asks whether the area of parallelogram can be found only using the information provided above.
Area of parallelogram = base x height
If we cut off one end to form a triangle and place it on the end, we would get a rectangle that looks like:
But we still do not know the width of rectangle in order to calculate area. Can we assume that not enough information is provided?
Yes, you can assume that. Just try two different $x$ values to demonstrate it.