Roughly, the perimeter of the room, including the sitting area, would be 65.909 ft squared. The perimeter of the semicircle would be approximately 13.909 ft. Then, add it to the 24 (12 x 2) and 28 (14 x 2), and you get 65.909 ft squared. As for the area, it would 168 (12 x 14) + pi (3.1415...) x 6 squared (radius squared - radius is half of the diameter) divided by two (since it's a semicircle). So then, your answer would be about 224.54 square feet.