Strips of tape, with a total length of 184 cm., outline a rectangular shape on Greta's driveway. She spray paints the inside of the shape, whose length is 2 cm. longer than half of its width, and whose diagonal measures 68 cm., then peels off the tape border. Greta's little brother, Gabe, uses all of the discarded tape to create another rectangular shape, having the greatest area possible. How much greater is the area of Gabe's shape, compared to Greta's