The other thread just reminded me of a question I saw many years ago (In New Scientist IIRC) Consider the situation... Imagine a string wrapped all the way around the Earths equator. Now imagine a second string raised to a point 1M above the earths equator. Q: How much longer is the second string than the first. I am not searching for the answer here, simply the method. What was your solution, and how did you arrive at it?