okay so you take the 12 feet I'm pretty sure you multiply 12 and 30 and then that's one of your answers and then the 12 and a 75 you must put those to together and that's an answer and you subtract your 12 x 30 and you're 12 x 75 and that's how you get your answer I am pretty sure that's how you and that's how you get your answer I am pretty sure that's how you do it