A fool wants to tie a rope around the earth. So he buys a rope of 40,000 km and ties it around the world. His neighbour, also a fool, wants to do the same. Only he wants the rope on sticks 1 metre above the ground.
How much more rope does he need?
And how much more rope do you need when you use a tennis ball instead of the earth?
Answer
6 metres 28 centimetres.
x=2PI(r+1)-2PIr
x=2PIr+2PI-2PIr x=2PI
x=6.28
It does not matter what the radius of the circle is. You always need 2*pi metres more of rope for each additional metre of radius added.
