Calclating gradient

marco67

Hi all, I hope this is the correct place to post this question.
Can someone help me with calculating gradients from modern % to the good old fashioned 1 in 4 for example.
I sat watching the Giro yesterday afternoon, now I know the Zoncolan was steep but how would 22% translate.
I'm sure I covered this in maths at school, but that was a long time ago and i'm not even sure if I was listening anyway.
cheers
marco

Ciao Marco

Mosschops2

To get from % to x in y.....

you need to divide 100 by %. For example,

22%: 100 / 22 = 1 in 4.5
10%: 100 / 10 = 1 in 10
5%: 100 / 5 = 1 in 20

etc.

Basically 20% means "20 in 100", which is the same as "one in five".

Hopefully that makes sense, and is correct!!

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benjus

Yes, it is school maths. Gradient as a ratio (e.g. 1 in 4) is just another way of saying the fraction on quarter (1/4), which is another way of saying 25%.

To convert a ratio to a percentage, multiply the first number by 100, then divide it by the second number (e.g. 1 in 4 = (1 * 100) / 4 = 25%)

To convert a percentage to a ratio, divide 100 by the percentage to give the ratio. For example, 22% gives 100/22 which is 4.54, so the ratio is "1 in 4.54". You could then round it to "1 in 4.5" or "1 in 5".

marco67

Thanks Mosschops2
It makes sense, whether brain will function to calculate that when I hit the bottom of the hill remains to be seen.
cheers

Ciao Marco

oldwelshman

Well I watched the race last night and they said it was 22 degrees which I think not [:D]
If it was 22 degrees then from tirgonometry. 1/tan22 gives 2.5 which gives 1:2.5 or 40% so I guess they meant 22% [:D]

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Mosschops2

No worries marco67.

(Also, I think you meant to write "Calcliating" for the title!!! [;)])

<font size="1">Have you ever tried pressing Alt+F4 ??</font id="size1">

Mr Dood L Doo

Remember that the divisor in this fraction is not the horizontal distance, but is instead the incline distance. Counter-intuitive but that's how it goes.

The old 1 in 4 was based on the horizontal distance so really 1 in 4 equates to 24.3 degrees in new money.



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