Companies that manufacture canned goods use surface area every day! Each can will need a wrapper to indicate what it is they're holding, and each wrapper just so happens to be the lateral area of a cylinder. Every winter, Christmas rolls around and it can seriously save paper and energy if you found the surface area of your gift prior to wrapping it. That way you can cut out the exact amount of paper without having uneven sides that will eventually need trimming, or sizes that don't fit. Hope this helps!