# I can not get the answer from the book could you please explain

• Nov 14th 2008, 08:45 PM
camstill
I can not get the answer from the book could you please explain
Estimate the volume in metric units and compute the acual volume of the item:

Oil in a barrel that has a height of 1 m and a diameter of 0.5m

The answer in the book: 0.20mcubed
• Nov 14th 2008, 08:52 PM
mr fantastic
Quote:

Originally Posted by camstill
Estimate the volume in metric units and compute the acual volume of the item:

Oil in a barrel that has a height of 1 m and a diameter of 0.5m

The answer in the book: 0.20mcubed

The barrel is a cylinder I assume ....? With radius r = 0.25 m ....
• Nov 14th 2008, 10:58 PM
camstill
So don't you use the formula V=(pi)(rsquared)(l)

and I still don't get that answer
• Nov 15th 2008, 12:56 AM
ILoveMaths07
$V = \pi r^2h$

$r = \frac {d}{2} = \frac{0.5\ m}{2} = 0.25\ m.$

$\Rightarrow V = \pi \times (0.25)^2 \times 1$

$\Rightarrow V = 0.20\ m^3$ (correct to $2$ sig. fig.)

I hope that helps. :)

ILoveMaths07.
• Nov 15th 2008, 02:23 AM
mr fantastic
Quote:

Originally Posted by camstill
So don't you use the formula V=(pi)(rsquared)(l)

and I still don't get that answer

Then you're making a data entry error with your calculator.