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Maths

Community Veteran
Posts: 1,571
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Registered: 13-04-2007

Maths

Anyone any good at maths? I need to work out the amount of water in gallons it takes to fill a lake 4.5 acre's and 3 foot deep. I all so need to know the weight of the water.
Dont ask why as I may have to tell you
20 REPLIES
Community Veteran
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Registered: 15-06-2007

Re: Maths

Water weighs 10 lb per imperial gallon and 62.4 lbs per cubic foot
An acre is 4840 sq yds
So total volume - assuming it is 3 ft average depth - is 4.5 x 4840 x 9 x 3 cu ft = 588,060 cu ft = 16,397 tons = 3,672,928 imperial gallons
Alternatively
4.5 acres is 1.821 hectares and a hectare is 10,000 sq metres so the area is 18,210 sq metres and is 0.915 metres deep so the volume is 16,662 cubic metres and weighs about 16,662 metric tonnes
Typing error corrected  Embarrassed
craigyoung
Grafter
Posts: 208
Registered: 06-09-2007

Re: Maths

You can use my bottle to fill it up as soon as I've finished the last glass....hic.....

http://flickr.com/photos/jremigio/22486765/
Community Veteran
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Registered: 05-04-2007

Re: Maths

Google can be useful for things like this as it has a built in calculator. For example, enter the search term '4.5 acres * 3 feet in imperial gallons' and you'll get an answer. It's also more accurate doing that as Google's calculation will use many more significant figures than, say, Jim's one.
Community Veteran
Posts: 1,571
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Registered: 13-04-2007

Re: Maths

Cheers for that there is a fantastic maths \search engine at http://www.wolframalpha.com/ but couldnt work out the formula to enter
Denzil
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Re: Maths

Quote from: Oldjim
Alternatively
4.5 acres is 1.821 hectares and a hectare is 10,000 sq metres so the area is 18,210 sq metres and is 0.915 metres deep so the volume is 16,662 cubic metres and weighs about 16.66 metric tonnes

Err, you mean 16,660 metric tonnes.
James
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Re: Maths

Does he?
Isn't a cubic metre 0.1 cubic tonnes? ie. multiplied by 100 rather than 1000?
Perhaps not.  Long time since I studied Maths Cheesy
Community Veteran
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Re: Maths

Quote from: Denzil
Err, you mean 16,660 metric tonnes.
bugger - fixed  Embarrassed Embarrassed
Community Veteran
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Re: Maths

Quote from: Jameseh
Isn't a cubic metre 0.1 cubic tonnes? ie. multiplied by 100 rather than 1000?

You're getting yourself mixed up there - a measure of capacity/volume can't in any way 'equal' a measure of weight without some kind of link between the two (i.e. a given density).
But anyway. There are 1000 litres in a cubic metre, one litre of water weighs one kilogramme, and there are 1000 kilogrammes in one metric tonne. Therefore, one metre-cubed of water weighs one metric tonne. Smiley
Community Veteran
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Re: Maths

And none of this is mathematics, it's just elementary arithmetic. Wink
One definition (from Wikipedia  Huh ):
Mathematics is the study of quantity, structure, space, relation, change, and various topics of pattern, form and entity.
And: Elementary arithmetic is the most basic kind of mathematics: it concerns the operations of addition, subtraction, multiplication, and division. Most people learn elementary arithmetic in elementary school.
Community Veteran
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Re: Maths

Quote from: HPsauce
And none of this is mathematics, it's just elementary arithmetic. Wink
...

Their I beg to differ because none of the calculations have allowed for the absorption rate of the lake lining, which would account for a large volume of water until it reaches saturation point. This only applies if the lake does not have an impermeable membrane. Another missing factor is the angle and length of the slope from ground level to the deepest point. The description as it stands is of a lake with 3' vertical sides, which is not normally the case.
Community Veteran
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Registered: 05-04-2007

Re: Maths

Quote from: HPsauce
And none of this is mathematics, it's just elementary arithmetic. Wink
[...]
And: Elementary arithmetic is the most basic kind of mathematics

Is that not a contradiction? Huh
Community Veteran
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Re: Maths

No it's Wikipedia  Grin Grin
Community Veteran
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Re: Maths

Google has a calculator .. see http://www.google.co.uk/search?hl=en&q=4.5+acres+in+square+feet&meta=&btnG=Google+Search
It is great for converting units.
Wink
SW.
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Community Veteran
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Re: Maths

[me=Be3G]suggests godsell4 looks to the third reply in this thread...[/me]