Math CentralQuandaries & Queries


Question from Walter, a student:

What is the volume of a pipe 7.92 inches inside diameter and 22 km. long in cubic feet of water


...7.92 inches inside diameter ...

Ugh! Who made _that_ one up? Let's stick to one system of units.

1 inch = 2.54 cm [type "inch" into Google to get this if you don't know it]

so 7.92 in. is how many cm?________________

Volume of a cylinder = length x area

so we need to know area.

Area = π r2

(you knew, right) so we need to know radius

radius = diameter/2

= how many centimeters? __________

Now find the area ________________

and multiply by length

...and 22 km. long...

There are 100 cm in a meter and 1000 m in a km

so length in cm is ____________________

Multiply and get volume in cubic cm.___________

Now convert back [go to Google to find how many liters in a cubic foot; a liter is a thousand cubic centimeters.] And your answer cubic feet of water _____________________




After you have completed the steps outlined above not before you can check your answer using our volume calculator.


About Math Central


Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.
Quandaries & Queries page Home page University of Regina PIMS