check the picture below.
since the figure has two pairs of parallel sides, tis a parallelogram.
the area of a parallelogram is just base * height, in this case, the base is 12, and its height is "y" which is 7, so the area will just be 12 * 7.
now, the perimeter, well, we know what "z" is, so the perimeter will just be 12 + 7√2 + 12 + 7√2, or 24 + 14√2.