From there it s not hard to believe that adding 3 feet to a rope around the actual earth would raise it almost 6 inches.
													
																	Rope around the earth brain teaser. 
									
	
		
	
																	His neighbour also a fool wants to do the same only he wants the rope on sticks 1 meter above the ground. 
																	The idea is to imagine the earth is a cube or just a square really and ask yourself if you added say 8 feet to the rope how far would that raise it above the square earth. 
																	A really simple but still a little non intuitive fact about the circumference of a circle. 
																	Band around the earth puzzle. 
															
													
									
	
		
	
																	From the diagram it s pretty clear it s one foot. 
																	The circumference of the earth is approximately 40 000 kilometers and someone has just made a metal band that circles the earth touching the ground at all locations. 
																	So he buys a rope of 40 000 km and ties it around the world. 
																	A math brain teaser. 
															
													
									
	
		
	
																	You come along at night as a practical joke and add just 10 meters to its length one hundredth of one kilometer. 
																	If you tie a ribbon around the equator how much longer of a ribbo. 
																	In fact this brain teaser requires neither an exact measurement of the earth s circumference which in fact varies by many kilometers depending on which circumference you measure nor even an assumption that the earth has a circular cross sect.