math question

[bstewert]

Here's a quick math problem, which will be easy for some of you:

Yesterday I saw a huge plastic tank laying on its side on a flatbed truck, maybe for
underground water storage. The shape was like a 55-gal drum, except it was
12' in diameter and 20' long. How would you calculate how many gallons it would hold?

I wonder what would be stored in it, besides water.

 

[Cobleskill]

pi r squared is area of circle, times length is volume. 7.5 gallons per cubic foot

 

[Cobleskill]

I would think it might be a fuel tank.

 

[Dave Shepard]

I got 16,956 gallons.

 

[lumberjack]

6x6x3.14x20x7.48= 16,910 gallons.

 

[Dave Shepard]

7.48g/ft[SUP]3[/SUP] I'll have to remember that.

 

[treesmith]

Only a persnickety fellow would squabble over 2/100 of a gallon per cubic foot!

 

[lumberjack]

Hahaha

 

[bstewert]

From my Boing engineer friend:


Hello Bob,
The volume of a cylinder (or any regular solid) is the product of its area
and its length. In this case the cross-sectional area is 6ft * 6ft * 3.14 =
113 sq ft. If the length is 20 ft, then the volume is 20ft * 113 sq ft =
2260 cubic ft.

There are about 7.48 gallons per cubic foot, so the total volume of the tank
is 7.48 gal per cu ft * 2260 cu ft= 16,905 gallons. That is enough to cover
one acre of ground with about 1/2 inch of water. Or beer.

Makes me thirsty.