



 
Hi, The inside surface area of a cylinder is $\pi$ times the inside diameter times the length where $\pi$ is approximately 3.1416. You have a cylinder that has a diameter of 12 inches and a length of 5 miles. You need both dimensions in the same units so I am going to use feet. There are 12 inches in a foot and 5,280 feet in a mile so the inside surface of your pipeline is \[\pi \times 1 \times 5 \times 5,280 \mbox{ square feet.}\] I hope this helps,  


Math Central is supported by the University of Regina and the Imperial Oil Foundation. 