# Swimming Pool **URL:** \ **Category:** Factual Questions\ **Created:** [June 8, 2013, 3:30am UTC](https://boards.straightdope.com/t/swimming-pool/660447 "2013-06-08T03:30:07Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![lk1932](https://avatars.discourse-cdn.com/v4/letter/l/aeb1de/32.png) [@lk1932](https://boards.straightdope.com/u/lk1932)\ **Post date:** [June 8, 2013, 3:30am UTC](https://boards.straightdope.com/t/swimming-pool/660447/1 "2013-06-08T03:30:07Z")
How many gallons of water will it take to fill a round pool, 14 ft. in dia. and 48 inches high ---
**Author:** ![beowulff](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/beowulff/32/542_2.png) [@beowulff](https://boards.straightdope.com/u/beowulff)\ **Post date:** [June 8, 2013, 3:36am UTC](https://boards.straightdope.com/t/swimming-pool/660447/2 "2013-06-08T03:36:58Z")
Pi \* r \* r \* d 3.14 \* 7 \* 7 \* 4 = 615 cubic feet. There are 7.48 gallons/cubic foot, so 615 \* 7.48 = 4600 gallons ---
**Author:** ![chacoguy](https://avatars.discourse-cdn.com/v4/letter/c/50afbb/32.png) [@chacoguy](https://boards.straightdope.com/u/chacoguy)\ **Post date:** [June 8, 2013, 3:48am UTC](https://boards.straightdope.com/t/swimming-pool/660447/3 "2013-06-08T03:48:06Z")
> [@beowulff](#): > > 4600 gallons You can’t seriously expect us to accept ROUNDED NUMBERS! Think of the children! ---
**Author:** ![scr4](https://avatars.discourse-cdn.com/v4/letter/s/59ef9b/32.png) [@scr4](https://boards.straightdope.com/u/scr4)\ **Post date:** [June 8, 2013, 4:07am UTC](https://boards.straightdope.com/t/swimming-pool/660447/4 "2013-06-08T04:07:26Z")
> [@chacoguy](#): > > You can’t seriously expect us to accept ROUNDED NUMBERS! Think of the children! Seriously though, the OP only specified 2 significant digits, so it would be wrong to provide more precision for the answer. If the pool were specified as 14.00 ft in diameter and 48.00 inches high, the answer would be 4606 gallons. ---
**Author:** ![Joey\_P](https://avatars.discourse-cdn.com/v4/letter/j/919ad9/32.png) [@Joey\_P](https://boards.straightdope.com/u/Joey_P)\ **Post date:** [June 8, 2013, 4:53am UTC](https://boards.straightdope.com/t/swimming-pool/660447/5 "2013-06-08T04:53:56Z")
> [@chacoguy](#): > > You can’t seriously expect us to accept ROUNDED NUMBERS! Think of the children! 615 cubic feet then. (get it, now they’re cubed numbers) ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [June 8, 2013, 4:57am UTC](https://boards.straightdope.com/t/swimming-pool/660447/6 "2013-06-08T04:57:33Z")
> [@scr4](#): > > Seriously though, the OP only specified 2 significant digits, so it would be wrong to provide more precision for the answer. > > If the pool were specified as 14.00 ft in diameter and 48.00 inches high, the answer would be 4606 gallons. He’s not going to be happy when he has to go back to the store to get 48 more bottles of water. ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [June 8, 2013, 5:31am UTC](https://boards.straightdope.com/t/swimming-pool/660447/7 "2013-06-08T05:31:50Z")
> [@TriPolar](#): > > He’s not going to be happy when he has to go back to the store to get 48 more bottles of water. Or when he discovers that a few gallons evaporated while he went back to the store. ---
**Author:** ![cochrane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cochrane/32/10441_2.png) [@cochrane](https://boards.straightdope.com/u/cochrane)\ **Post date:** [June 8, 2013, 8:22am UTC](https://boards.straightdope.com/t/swimming-pool/660447/8 "2013-06-08T08:22:19Z")
> [@beowulff](#): > > Pi \* r \* r \* d > > 3.14 \* 7 \* 7 \* 4 = 615 cubic feet. > > There are 7.48 gallons/cubic foot, so 615 \* 7.48 = 4600 gallons While your answer is correct, I have to nitpick your formula slightly. The volume of a cylinder is Pi \* r \* r \* h, where h = height, which in this example would be the four feet. D would be the diameter, 14, which you correctly halved to give the radius. ---
**Author:** ![septimus](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/septimus/32/410_2.png) [@septimus](https://boards.straightdope.com/u/septimus)\ **Post date:** [June 8, 2013, 9:08am UTC](https://boards.straightdope.com/t/swimming-pool/660447/9 "2013-06-08T09:08:35Z")
> [@lk1932](#): > > How many gallons of water will it take to fill a round pool, 14 ft. in dia. and 48 inches high [Let me Google that for you.](http://lmgtfy.com/?q=7+feet+*+7+feet+*+48+inches+*+3.1416+%2F+%20(1+gallon)) ---
**Author:** ![shijinn](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@shijinn](https://boards.straightdope.com/u/shijinn)\ **Post date:** [June 8, 2013, 9:12am UTC](https://boards.straightdope.com/t/swimming-pool/660447/10 "2013-06-08T09:12:59Z")
> [@cochrane](#): > > While your answer is correct, I have to nitpick your formula slightly. The volume of a cylinder is Pi \* r \* r \* h, where h = height, which in this example would be the four feet. D would be the diameter, 14, which you correctly halved to give the radius. i think his d = depth. ---
**Author:** ![tellyworth](https://avatars.discourse-cdn.com/v4/letter/t/977dab/32.png) [@tellyworth](https://boards.straightdope.com/u/tellyworth)\ **Post date:** [June 8, 2013, 9:17am UTC](https://boards.straightdope.com/t/swimming-pool/660447/11 "2013-06-08T09:17:56Z")
> [@septimus](#): > > Let me Google that for you. Or you might prefer [something expressed a bit more naturally](http://www.wolframalpha.com/input/?i=how+many+gallons+in+a+cylinder+14%27+diameter+and+48%22+high). ---
**Author:** ![chappachula](https://avatars.discourse-cdn.com/v4/letter/c/d2c977/32.png) [@chappachula](https://boards.straightdope.com/u/chappachula)\ **Post date:** [June 8, 2013, 11:48am UTC](https://boards.straightdope.com/t/swimming-pool/660447/12 "2013-06-08T11:48:04Z")
> [@TriPolar](#): > > He’s not going to be happy when he has to go back to the store to get 48 more bottles of water. Maybe not… but I’ll bet he’s happy that we solved his homework problem for him 🙂 ---
**Author:** ![CookingWithGas](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cookingwithgas/32/485_2.png) [@CookingWithGas](https://boards.straightdope.com/u/CookingWithGas)\ **Post date:** [June 8, 2013, 12:02pm UTC](https://boards.straightdope.com/t/swimming-pool/660447/13 "2013-06-08T12:02:10Z")
> [@chappachula](#): > > Maybe not… but I’ll bet he’s happy that we solved his homework problem for him 🙂 > [@](#): > > About lk1932 > > Occupation > retired Probably not 🙂 ---
**Author:** ![leahcim](https://avatars.discourse-cdn.com/v4/letter/l/b4bc9f/32.png) [@leahcim](https://boards.straightdope.com/u/leahcim)\ **Post date:** [June 8, 2013, 1:27pm UTC](https://boards.straightdope.com/t/swimming-pool/660447/14 "2013-06-08T13:27:25Z")
> [@chacoguy](#): > > Think of the children! The problem does not give the number or total volume of children in the pool. Naturally, you should subtract the volume of their submerged portions from the final answer. ---
**Author:** ![moriah](https://avatars.discourse-cdn.com/v4/letter/m/b2d939/32.png) [@moriah](https://boards.straightdope.com/u/moriah)\ **Post date:** [June 8, 2013, 5:01pm UTC](https://boards.straightdope.com/t/swimming-pool/660447/15 "2013-06-08T17:01:10Z")
> [@leahcim](#): > > The problem does not give the number or total volume of children in the pool. Naturally, you should subtract the volume of their submerged portions from the final answer. European or African children? ---
**Author:** ![Lanzy](https://avatars.discourse-cdn.com/v4/letter/l/74df32/32.png) [@Lanzy](https://boards.straightdope.com/u/Lanzy)\ **Post date:** [June 8, 2013, 5:22pm UTC](https://boards.straightdope.com/t/swimming-pool/660447/16 "2013-06-08T17:22:12Z")
Insert hose, turn on, wait around…full? Turn off. Empty pool into bottles, count bottles, put back in pool. ---
**Author:** ![cochrane](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/cochrane/32/10441_2.png) [@cochrane](https://boards.straightdope.com/u/cochrane)\ **Post date:** [June 8, 2013, 6:31pm UTC](https://boards.straightdope.com/t/swimming-pool/660447/17 "2013-06-08T18:31:05Z")
> [@shijinn](#): > > i think his d = depth. OK. That sounds reasonable. They are the same thing. ---
**Author:** ![Machine\_Elf](https://avatars.discourse-cdn.com/v4/letter/m/82dd89/32.png) [@Machine\_Elf](https://boards.straightdope.com/u/Machine_Elf)\ **Post date:** [June 8, 2013, 7:00pm UTC](https://boards.straightdope.com/t/swimming-pool/660447/18 "2013-06-08T19:00:36Z")
> [@beowulff](#): > > Pi \* r \* r \* d > > 3.14 \* 7 \* 7 \* 4 = 615 cubic feet. > > There are 7.48 gallons/cubic foot, so 615 \* 7.48 = 4600 gallons The pool is 48 inches high. You are planning on filling it right up to the rim? How about leaving a few inches at the top so the pool doesn’t overflow when the kids climb in? ---
**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\ **Post date:** [June 8, 2013, 11:02pm UTC](https://boards.straightdope.com/t/swimming-pool/660447/19 "2013-06-08T23:02:41Z")
> [@chacoguy](#): > > You can’t seriously expect us to accept ROUNDED NUMBERS! Think of the children! Yes he does expect ROUNDED NUMBERS. Read the OP, **chacoguy**! It’s a ROUND pool! 😛 That said, though, we have another problem: > [@Joey\_P](#): > > 615 cubic feet then. > > (get it, now they’re cubed numbers) Okay, then, how do you fill a ROUND pool with CUBES of water? (Yes, yes, I’ve studied Calculus and I understand that you can fill the round pool with water cubes, to a closer and closer approximation, by using smaller and smaller water cubes. This is a simple application of Triple Integration. But in this problem, we’re specifically using FOOT CUBES, which can at best give us a ROUND result. There’s a 4-foot deep paradox in there somewhere.) (ETA: Traditionally, the volume of kids would be ignored for problems like this, until you get into Differential Equations.) ---
**Author:** ![Washoe](https://avatars.discourse-cdn.com/v4/letter/w/ecae2f/32.png) [@Washoe](https://boards.straightdope.com/u/Washoe)\ **Post date:** [June 8, 2013, 11:40pm UTC](https://boards.straightdope.com/t/swimming-pool/660447/20 "2013-06-08T23:40:25Z")
> [@Senegoid](#): > > Okay, then, how do you fill a ROUND pool with CUBES of water? Wait for them to melt? [Next page](https://boards.straightdope.com/t/swimming-pool/660447.md?page=2)