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Posted: 8/21/2017 7:59:08 PM EDT
I have a pipe that is 3 feet high and 4 feet in Dia. how many gallons of water will it hold?


Figure area of 4' circle  pi x radius squared = sq. ft. of area
x 3 (depth of tank) = cubic ft. of volume in tank 1 cu. ft. = 7.48 gal What are you, in the third grade? 




1 US gallon is 231 cubic inches.
or (231 inch^3)(1 foot/12 inch)^3 to convert to cubic feet. The cross section area is (pi/4)X[Diameter]^2. I have no idea why the radius version of this relation is taught since we more often refer to dimensions as diameters, and it's more complicated. 

Easy thing to remember when calculating volume of a cylindrical shaped container....
A circle takes up 78.54% of a square. Calculate cubicle feet as you normally would and then multiply by .7854. If you're looking for gals there are 7.4805 gals/cubic foot. So..... Using ID (LxWxH) .7854 x 7.4805 

Quoted:
Is that lower real? If so where'd you get it? View Quote 


Quoted:
Easy thing to remember when calculating volume of a cylindrical shaped container.... A circle takes up 78.54% of a square. Calculate cubicle feet as you normally would and then multiply by .7854. If you're looking for gals there are 7.4805 gals/cubic foot. So..... Using ID (LxWxH) .7854 x 7.4805 View Quote 

OP, if you need to do this regularly:
The area of a circle is pi times the radius squared. The radius is half the diameter. To find the volume of a cylinder, you need to multiply the area by the height. Think about this (the volume part; you just have to memorize the area part) for a moment and it should make sense. 

I'm not sure why everyone is either wrong or harassing.
you have a 4 ft diameter tank that is 3 ft high. the area is 2 ft x 2 ft * Pi = 4 ft^2 * Pi the volume is the area * height = 4 ft^2 * Pi * 3 ft = 12 ft^3 * Pi = 37.6991118431 ft^3 I have no idea what the conversion rate is, but according to google it's equal to 282.0089405405922 gallons 


Quoted:
I have a pipe that is 3 feet high and 4 feet in Dia. how many gallons of water will it hold? View Quote Cylinder volume is pi x inside radius squared x height. 

Well, OP you've got several answers. And at least one of them is correct. How will you decide which one is correct?






Are there caps on the end of the pipe? Cause otherwise the water is probably just going to spill out onto the ground.



This certainly should be a poll question with pi as one of the choices.


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