 |
| ||
| |||
|
| Math Central | Quandaries & Queries |
|
Question from sharon: We have a cistern to hold spring water that measures 12 feet in depth by 5 feet in diameter. How much in liquid gallons will it hold? |
Hi Sharon,
I remember that there are 231 cubic inches in a US gallon so I am going to change your dimensions to inches. Thus your cistern is 12 × 12 = 144 inches deep and has a radius of 5/2 × 12 = 30 inches. The volume of a right circular cylinder is
π r2 h
where r is the radius and h is the height. Thus your cistern has a volume of
π × 302 × 144 = 407,150.40 cubic inches.
Which is
407,150.40/231 = 1,762.6 US gallons.
Penny
| ||
| ||
| ||
 |
 |
|
Math Central is supported by the University of Regina and The Pacific Institute for the Mathematical Sciences.