quote:Originally posted by Jim Gerweck:
Unless you've got a decimal foot tape, it's very hard to locate 3.10686 miles, whereas 1609.344 is easily locatable on a metric tape.
But the real reason should be that the mile is defined by an exact metric distance, but the converse is not true - Imperial equivalents are just approximations - maybe sufficiently accurate for our purposes, but why introduce another possible source of error that's not needed? For instance, if I convert 5km I get 3.106856 miles. But then if I convert that figure back, I get 5.0000001 km, indicating there's some imprecision creeping in here.
Jim, I can see this both ways, but I generally agree with Duane. Jones counts cannot feel the difference between metric and Imperial.
The reason for the miniscule conversion difference you find is of course rounding. Using the free download CONVERT.EXE, I find that 5 kilometers is 3.106856 - exactly. Reversing this conversion yields 5K - exactly.
The Hubble telescope would not have needed its first servicing mission had NASA mirror engineers used this simple tool.