The relationship between the metric and 'english' units of measure are
as wide-ranging and unique as any relationship defined by humans can
be. Both the metric system and the imperial system of measurement have
experienced many iterations over their history, with the metric system
(being the newer of the two) seeing the most refinement over the last
132 years due to the advances in humanity's understanding of the
physics of the universe.
An excellent resource for you to get an overview of the relationship
between modern metric (SI) and imperial units can be found here:
A Dictionary of Units - by Frank Tapson
On this page, the author cites the exact, internationally accepted
definitions of the base SI units including the metre. To see how this
unique definition was arrived at, you should read the history
maintained on the official SI website:
You will observe that metric base units are all based on physical
constants, that is, occurences in nature that can be repeatably
measured. The only measurement that is not purely a measurable
phenomenon is the base unit of weight, the kilogram; this continues to
be defined by a man-made prototype that has been measured very
precisely to the best abilities of modern science.
The Imperial/US systems of measure, on the other hand, are essentially
still based on the science of 'biblical' times, as modified through
the ages. An excellent and interesting page to read about the
historical evolution of the 'english' measurements can be found at:
Here, we can find a couple of interesting tidbits:
"in Old England, the mile - derived from the Roman "mille passus" or
1000 double steps - was originally 5000 feet long as in the Roman
definition (1 "passus" = 5 feet). Later, it took 5280 feet to
accomodate exactly 8 furlongs, the most popular measure of the time.
Actually, the usual happened : the foot and the rod went slowly their
separate ways, being used by different industries (the weaver and the
farmer ...) Things had to be straightened up and, as the foot and the
rod were already entrenched, we find these strange figures : 16.5
ft/rod and 5280 ft/mile. This was voted by the House under Queen
Elizabeth I in 1595.
It should be noted that the furlong comes from the Greek and Roman
stadion, which they themselves inherited from more ancient times. It
seems to be the optimal length for the traditional plough."
"The rod was determined by lining up 16 men (after the Sunday Service,
the story goes) and measuring the combined lenght of all their left
feet. These 16 feet make up 16.5 "feet". Thickness of the shoes ? Gaps
between feet ? This is tradition ..."
Of particular note is the fact that, up until 1595, the mile was
defined as 5000 feet; it was redefined as 5280 feet to accommodate
standardization of measurements across trades. Elsewhere on this page,
you can read about how the basic units of measure were constantly
being revised over the years to try to correct for errors (intentional
and otherwise) that crept in over the years, as well as to accommodate
for the whim of whoever was the ruler of the (English) nation at the
All of this is to say that yes, it is completely a coincidence
(meaning, not by design) that the conversion factor between a mile and
a kilometre is approximately 1.609, which in turn is close to the
Golden Ratio. Imperial measures are derived from the science of
ancient history (ie. what could be easily observed with the human
eye), while metric measures are based on the science of modern times
and humanity's understanding of the physics of the universe.
Incidentally, the US National Institute of Standards and Technology,
Weights and Measures Division, maintains the official US guide for
measurement systems and conversions. Their website is:
and the relevant publication is:
I hope this is helpful!
Google Answers Researcher