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CONVERTING MILES AND KILOMETRES

Here's a mnemonic device for recalling how to easily convert miles to kilometres and vice-versa, supplied by Francis Garcia of Woking, GB:

Use Fibonnacci Numbers

1, 2, 3, 5, 8, 13, 21, 34, 55, 89 etc

Fibonnacci numbers begin at 1,2 and extend in an infinite series by adding the last two numbers to get the next (ie. 1+2=3 and 2+3=5). And amazingly, any two consecutive Fibonnacci numbers give a fairly accurate "mile" and "kilometre" conversion. For example:

13 miles = 21 km!
21 miles = 34 km!

Miles are "imperial scale" measures while kilometres are "metric scale", but a "Fibonnacci" method of approximate conversion is surprisingly accurate compared with calculations using proper conversion formulas. Compare the figures in the charts below:

miles km(Fib.) km(exact) 1 mile = 1.609 km 1 2 1.61 2 3 3.22 3 5 4.83 5 8 8.04 8 13 12.87 13 21 20.92 21 34 33.79 34 55 54.71 55 89 88.50 89 144 143.20

km miles(Fib.) miles(exact) 1 km = 0.6214 miles 2 1 1.24 3 2 1.86 5 3 3.11 8 5 4.97 13 8 8.08 21 13 13.05 34 21 21.13 55 34 34.18 89 55 55.30 144 89 89.48

The Fibonnacci numbers themselves don't have to be memorised - the series can easily be recreated on paper at any time, to provide the conversion figures required. That's easier than having to memorise and multiply conversion formulas!

The Fibonnacci method can also be used to convert numbers that are not in the series. Take 40 miles or km for example - to convert it, first break down the 40 into a combination of simple Fibonnacci numbers, ie. (13*3)+1. Then any multiplication still required is relatively simple to perform, e.g.:

Fib: 40 miles = (13*3)+1 = (21*3)+2 km = 65 km
compare formula: 40 miles = 40*1.609 = 64.36 km

Fib: 40 km = (13*3)+1 = (8*3)+0 m = 25 miles
compare formula: 40 km = 40*0.6214 = 24.86 miles

Lastly, if confused about which way round the conversions go, remember that distances in miles and kilometres are like the number of letters in each word:

less in miles and more in kilometres!

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