Hi, there is this one problem I have and five continuations of it. I can't figure out the first problem, meaning I can't figure out the continuations. Could someone help me? And quickly preferably so I can finish my math hw? =(

The figure shows a long rectangular strip of paper, one corner of which has been folded over to meet the opposite edge, thereby creating a 30 degree angle. Given that the width of the strip is 12 inches, find the length of the crease.