Maths Help - Easy Question - Need Clarification Please

Captain-Fungi · 3 Dec 2006 at 12:57

Guys,

Can someone please check that my workings below are correct, i'm fairly certain they are but something keeps nagging at me telling me that I am wrong. I would ask someone else but there is nobody home

The volume of a cylinder can be obtained using the formula V=LC^2/4pi

So: Volume = L * C squared divided by the product of 4 times pi.

The values I have for L and C are: L = 3.50m and C = 75cm

What is the approximate volume in meters cubed?

I got the approximate answer as 16m^3 and the exact answer as 15.66m^3 (2 d.p) Is this correct?

All help greatly appreciated.

Thanks

Inquisitor · 3 Dec 2006 at 13:06

I got 0.15667 m³ for V. Did you convert C from cm to m?

m3csl2004 · 3 Dec 2006 at 13:13

i agree with above

PinkPig · 3 Dec 2006 at 13:24

Inquisitor said:
I got 0.15667 m³ for V. Did you convert C from cm to m?

Agree with this.

Angus-Higgins · 3 Dec 2006 at 13:27

I got: 0.15666814710608447114749495456992m^3

Did you do (L * C)^2 or L * C^2?

Angus Higgins

crunchman · 3 Dec 2006 at 13:42

Inquisitor said:
I got 0.15667 m³ for V. Did you convert C from cm to m?

Looks like he converted L to cm.

Captain-Fungi · 3 Dec 2006 at 13:42

Angus-Higgins said:
I got: 0.15666814710608447114749495456992m^3

Did you do (L * C)^2 or L * C^2?

Angus Higgins

I did L * C^2

I converted into cm first, maybe I went wrong somewhere?

Oh and L is length and C is circumference.

Aod · 3 Dec 2006 at 13:43

then your units will be cm^3.

http://www.google.com/search?client=opera&rls=en&q=1m^3+in+cm^3&sourceid=opera&ie=utf-8&oe=utf-8

i'm confused....

not enough tea i say...

Inquisitor · 3 Dec 2006 at 13:45

If you work in centimetres, you should get rougly V = 156,670 cm³, which is 0.15667 m³.

JonC · 3 Dec 2006 at 13:50

Captain-Fungi said:
I did L * C^2

I converted into cm first, maybe I went wrong somewhere?

Oh and L is length and C is circumference.

If you convert into cm first, you have to divide your answer by 100 for each dimension to convert it into m^3.

For example if you have a cube that is 1m x 1m x 1m, you have a cube that is 100cm x 100cm x 100cm, so in order to convert a volume from cm--> m, you have to divide by 100 x 100 x 100.

It sounds like you have divided by 100 x 100 (once for each measurement), but you need to divide by 100 again as the C measurement is squared ( eg (m x100)^2 = m^2 x 100^2).

Captain-Fungi · 3 Dec 2006 at 13:52

JonC said:
If you convert into cm first, you have to divide your answer by 100 for each dimension to convert it into m^3.

For example if you have a cube that is 1m x 1m x 1m, you have a cube that is 100cm x 100cm x 100cm, so in order to convert a volume from cm--> m, you have to divide by 100 x 100 x 100.

It sounds like you have divided by 100 x 100 (once for each measurement), but you need to divide by 100 again as the C measurement is squared ( eg (m x100)^2 = m^2 x 100^2).

You are correct, I can see where I went wrong.

Thanks to everyone for their input.