how would i find the area of the parallelogram if the area of each right triangle region is 7 1/2 square inches

Since a parallelogram need not have any right angles, I assume that your diagram shows the intersecting diagonals of a rhombus or square. They do form right angles.

So, since there are 4 such triangles, the area of the parallelogram is 4*7.5 = 30 sq in.

If this interpretation is faulty, please explain further the figure in question.