Imagine you would have to put a rope around the moon. Since the moon is 1,738,000 metres in diameter, this is a hard task. Finally you have managed to get the rope around the moon but... it is one meter short.

You decide to dig a groove all around the moon, so that the shorter rope suffices. How deep must this groove be? (Assume the Moon to be a perfect sphere.)

The rules don't change. Circumferance is (and always will be) D*pi. Therefore, C/pi=D. If the rope is 1M short, then (C-1)/pi=(C/pi)-(1/pi)=D-(1/pi)=1,737,999.68M, so your groove is about 12 inches deep.

Posted by Dan Dise on 2002-05-07 13:45:41