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# Pretty geeky but....

I am a massive geek so found this an intersting little fact. Maybe work these conversions out in your head on a long run if you need to take your mind of the pain for a bit. Although there are prob better things to think about.

http://www.catonmat.net/blog/using-fibonacci-numbers-to-convert-from-miles-to-kilometers/

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Hmmm.. sort of interesting (and it probably has occurred to me at one point or another), but essentially just a way of pointing out that the "Golden ratio" 1.618 is quite close to the ratio of Km: Miles, 1.609.

What I find useful is simply remembering one or two close approximations (some of which do indeed occur in the Fibonacci sequence) and using these for any calculations, e.g.

5 miles = 8 km
6.2 miles = 10 km
10 miles = 16 km,
...so 26 miles = 10M+10M+6M = 16 + 16 + 10 = 42 km

• yeah it is a total coincidence, but you can tell your friends in the pub if you want to really bore them

Fibonacci number is any number in a fibonacci sequence which is

0, 1, 1, 2, 3, 5, 8, 13, 21

where the next number in the sequence is the sum of the 2 previous.

• 5/8ths is a close enough approximation for me, and it's pretty quick to calculate. I hadn't thought of this being close to the Golden ratio before though, so that's kind of interesting, i guess.

• zzzzzzzz

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The number to remember is

0.6214

Km to miles you multply by.

Miles to Km you divide by.

• David Falconer 3 wrote (see)
RicF wrote (see)

The number to remember is

0.6214

Km to miles you multply by.

Miles to Km you divide by.

Hahaa, are you taking the P..s ric ......... so you're running along in a marathon, you're knackered ....... its the 18 mile mark, and you're thinking to yourself .... ok 8.2 divided by 0.6214 is....... yeah right ......... lets be sensible yeah?

That particular mental calculation would probably be beyond me, but I sometimes distract myself by counting backwards from a very high number, in sevens.

The other way to convert miles/kilometers which is more manageable in your head is to multiply by eight and divide by five, or vice versa.  Not completely precise, but pretty close.

• I just switch my GPS between metric and imperial, sorted.

I do sometimes distract myself by working out what percentage of the run I've completed.

Calculating n! for increasing values of n is another good one. i.e.

1 x 2 x 3 x 4 x 5 x 6 ...

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Easy for me Falconer. Its all multiples of 6 minutes.

You know, 6 mins, 12 mins, 18 mins at 1 mile, 2 mile, 3 mile. etc.

10 x 6 = 60

Oh look! the 10 mile marker and the watch only says 58 mins.

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You've lost me now.