well first u need a calculator then multiply the wait i messed up u need to find the base and the height the base is 16 in then the height is 5 so after u do that u meed to multiply is so easy with a calculator then u divide
subtract dat answer then the answer u get add by 3+6+3+3+7 but subtract 16 when u equal the the frist answer u got subtract by 16 then thats how u will get your anwser