Thanksgiving Trivia

Well not trivia exactly, but another riddle found on the internet:

Kottke posted a riddle he found at 3 Quarks Daily:

You are given two ropes and a lighter. This is the only equipment you can use. You are told that each of the two ropes has the following property: if you light one end of the rope, it will take exactly one hour to burn all the way to the other end. But it doesn’t have to burn at a uniform rate. In other words, half the rope may burn in the first five minutes, and then the other half would take 55 minutes. The rate at which the two ropes burn is not necessarily the same, so the second rope will also take an hour to burn from one end to the other, but may do it at some varying rate, which is not necessarily the same as the one for the first rope. Now you are asked to measure a period of 45 minutes. How will you do it?

Well guys, I’ve only spent a couple of minutes on this one but I certainly haven’t managed to figure it out yet. I mean, I have no idea. 3 Quarks Daily is going to post the answer to this (and 13 other riddles that were posted with it, most of which I think I know the answer to) sometime next week, but I can’t wait that long. What’s the answer?

Obviously, somebody may put the answer in the comments below, so be judicious in looking if you want to try to figure it out on your own.