Hello,
To answer your problem, use the Pythagorean Theorem for 2 right triangles and the Area of a Rectangle to find the Area of the Parallelogram.
All together:
A = 2(area of right triangle) + (area of rectangle)
A = 2[1/2*b*h] + [b*h]
To find the area of the parallelogram, I would be here for a while. Haha