Working out area / volume

[billybongo]

Would one of you bright people be so kind as to show me how to work out
the area of a cylinder 900mm high x 450 dia and subsequently the volume. I have looked at other net sources but cant see the wood for the trees , many thanks mark

 

[justlead1]

Hi. The formula is pie r squared times length. Eg 450 mm diameter divided by 2 will give you radius. (also work in metres rather than mm)
So 0.450 / 2 = 0.225
0.225 x 0.225 = 0.0506 x 3.142 (pie) = 0.01589 (area in M squared) x length= 0.0589 x 0.9 =0.143 cubic metres x by 1000 = 143 litres and mass in Kg at 4 degrees C (to gallons divide by 4.55)

 

[Spudhater]

Get an i phone, they have an "apt" for that ..... the lad that has been with me uses his for everything .

 

[kirkgas]

Hi. The formula is pie r squared times length. Eg 450 mm diameter divided by 2 will give you radius. (also work in metres rather than mm)
So 0.450 / 2 = 0.225
0.225 x 0.225 = 0.0506 x 3.142 (pie) = 0.01589 (area in M squared) x length= 0.0589 x 0.9 =0.143 cubic metres x by 1000 = 143 litres and mass in Kg at 4 degrees C (to gallons divide by 4.55)

this calculation would be correct if the cylinder was round with square top, but it has a domed top, the capacity of a 900x450 is 117litres, (i googled copper cylinder and looked at someones product sheet)

 

[Steve001]

[DLMURL="http://www.newarkcoppercylinder.co.uk/cylinders/information/capacitycalc.php"]Cylinder Capacity Calculator | Newark Copper Cylinders[/DLMURL]

Any good?

if it helps a litre of water weighs approx 1kg and fills 100mm x 100mm x 10mm depeding on temp i think

 

[billybongo]

Thanks for all your inputs , would you believe this is a question on a test paper for school leavers looking to get into plumbing .

 

[Plumbstar Tom]

in that case then the word cylinder states it is a standard cylinder and has nothing to do with a copper cylinder used in plumbing

One would ask why this question is on here??? As it is strictly a mathematic natured question

The answers you require are:

Area = 450 x pi x 900 = 1,272,345.02 mm^2

or 1.272 m^2

Volume = (450/2)^2 x pi x 900 = 143,138,815.00 mm^3

or 0.143 m^3

 

[Toddyplumb]

I would think that this is quite a logical question for a school leaver wanting into plumbing, and I would expect the correct answer !

 

[Plumbstar Tom]

logical in a way but being a written exam paper question it is regardind a stand perfect cylinder, not a hot water cylinder as this is not mentioned in the question

So a domed top or what ever is irrelevant

 

[billybongo]

Plumstar tom , sorry if you think the question should not be on the forum and wasteing valuable space , most people didnt seem to look at it from that angle thankfully .

 

[Plumbstar Tom]

i take it back, i miss the part where it was on a paper for 'wannabe plumbers'

but it must be assumed it is a standard cylinder and not a hot water cylinder otherwise the question is unanswerable

 

[justlead1]

Hi. Billybongo I agree a bit of arithmetic is paramount in the plumbing and heating trade. Without it all sorts of thing can be installed below par. And often are.

 

[billybongo]

It was the drawing of a standard cylinder and as said school leavers should know this .
Its a long time since ive dealt with this sort of thing , a workmate brought the paper in as it was for his lad , it also had a drawing of a fully pumped system and he had to name the components , quite easy i guess when you can bring the paper home .

 

[tamz]

The actual capacity of a 450 x 900 cylinder is as kirk says 117 litres. When measuring the height measure to the bottom of the dome eg 740. As the bottom is concave it cancels the top dome out.
so 3.142x.225x.225x.74=0.1177m2=117litres=117kg