







A barrel on its side 
20081113 

From Dave: Question from Dave:
How many gallons are left in a 36x60 in. barrel (laying on its side) and has 16 in. of gasoline left. I have attached a diagram. Answered by Harley Weston. 





A barn roof 
20160529 

From Joe: Is it possible to build a barn roof (irregular pentagon?) with a 12' base and the other 4 sides 4' each? Thanks. Answered by Penny Nom. 





An oil field barrel 
20150802 

From Michael: I have a storage tank that is 12' diameter x 22.5' high
it's capacity is 450 oil field barrels (42 gallon)
Which would hold 19,036 us gallons
I'm trying to find out how many inches it would take to make 1 barrel
I was able to get this far by using your volume calculator, but haven't been able to come up with the rest!
Thank you very much for your time, and I really appreciate this site and the tools you all have made available to everyone for free!
Hope to hear back from you soon and God bless you all!! Answered by Penny Nom. 





The surface area of a round bar 
20150606 

From chirag: Please tell me the formula for finding round bar surface in square inches/ mm Answered by Penny Nom. 





Barrels of oil 
20140416 

From daryl: Looking for an accurate number to use when calculating barrels per inch in a a tank with the following dimensions:
Nominal diameter  15'6", nominal height  16ft, nominal capacity  500 barrels. These are commonly referred to as 500x16 tanks.
Currently we are using 2.6 barrels per inch. We need 180 barrels for a full load so I'm trying to figure out how many total inches I need to load 180 bbl. This has been a matter of debate for some time. Thanks for your help. Answered by Harley Weston. 





A goat tied to a rectangular barn 
20081102 

From Misty: If there is a goat tied to a rectangular barn on a 50 foot
lead and the barn is 20 feet by 20 feet (floor).
When the rope goes around the barn, what is the new
radius and How much of a circle can it make without hitting the barn or
overlapping area you've already found and What is that area? Answered by Stephen La Rocque. 





How many gallons of fuel still in the barrel? 
20080722 

From Charles: I have barrel 6 feet long and 3 feet diameter that is laying on it's side with 5 inches of fuel, how many gallons of fuel still in barrel Answered by Penny Nom. 





Repeating decimals 
20080129 

From Malise: Write each repeating decimal using bar notation.
0.428571428... Answered by Penny Nom. 





How many barrels of liquid will it hold? 
20070928 

From Jason: A tank is 8' wide by 8' tall x 45' long. How many barrels of liquid will it hold?? Answered by Stephen La Rocque and Harley Weston. 





Relating volume to depth in a cylindrical container 
20070419 

From Dan: I have a cylindrical polyethylene rain barrel 23" in diameter and 35" high. If I've calculated correctly thus far, its volume is:
14, 547.49 cubic inches (or 8.418686 cubic feet or 0.31 cubic yards)
and could, ideally, contain 62.6 gallons of rain water whose weight would be 525.32 lbs. (62.4 lbs./cubic foot X 8.418686).
I'm having difficulty relating inch depth markings on the side of the barrel to volume capacity; i.e., how many inches in depth
in a cylinder of the size given would = how many gallons (or quarts) of water. The barrel stands upright on its end and is, thus, 35" high
when oriented in this fashion, much as a 55gallon oil drum appears when similarly stowed.
Dan Watley Answered by Stephen La Rocque. 





How many barrels would this container hold per inch? 
20070310 

From LaDonna: My container is 50" across and 40.5' ft. long. I believe it would hold 140 barrels. If measuring, how many barrels would this container hold per inch? Answered by Penny Nom. 





10 friends run into each other at a bar 
20060819 

From Ken: 10 friends run into each other at a bar. We will name them A,B,C,D,E,F,G,H,I AND J.
They all leave at the same time heading for seperate bars. However, A runs into B, C runs into D, E runs into F, G runs into H and I runs into J. These five groups leave again and the same thing keeps happening, but each time running in to someone they have not run into before. How many bars will it take, with each person meeting the others only once, until all of them have met each other again? Answered by Chris Fisher. 





A perpendicular intersection of two barrel vaults 
20060721 

From Neal: I'm wanting to build a series of architectural models of different roman and medieval buildings out of cardboard. Once I have perfected the models I want to print them out on card stock so that school kids (or anyone else) can make the buildings.
A feature of many of these models is the cross or groin vault (a perpendicular intersection of two barrel vaults).
A single barrel vault is easy to imagine as a plane (a rectangular piece of cardboard) that will be folded into a semicircular arch.
The intersection of a second barrel vault and this one is presenting me with problems. The second plane needs to have an ellipse cut into it so that when it is folded into the arch, it will mate up with the curve of the first barrel vault.
Given that the two pieces of card have identical widths (and therefore identical arcs in cross section) is there a way to calculate the ellipse that needs to be cut so that it can be cut before the second arch is folded? Answered by Edward Doolittle. 





Barrels of oil in a tank 
20060109 

From Francis: How many barrels of oil (42 gallons of oil in one oil tank) would there be in an oil tank that was 15 feet tall and 10 feet across? Answered by Penny Nom. 





The bar over repeating digits. 
20040907 

From Debbie: I would like to know the name given to the bar that is written over the repeating digits of a decimal. Answered by Penny Nom. 





The horizontal fraction bar 
20040527 

From Kashia: What is the name of the bar that separates a numerator and that denominator? Answered by Penny Nom. 





X bar 
20031104 

From mary: Remind me what this means:
_
X
Answered by Andrei Volodin. 





Double bar graphs 
20010909 

From Leslie: My daughter has a homework problem in which she is graphing data from two frequency tables onto a double bar graph. The graph shows how many students worked in a program in two different years, grouped by age. In the first age group, one of the years has no students working, while there were students in that age group in the other year. Answered by Penny Nom. 





A bargin with the devil 
20010321 

From DJ: There once was a boy who spent all his time dreaming about getting rich. " I would do anything to be rich". The devil, hearing this, appeared before the boy and offered to make him rich. "See that bridge?" said the devil. Just walk across and I will double your money you have now. In fact, each time you cross I will double your money. There is just one thing you must give me $24 after each crossing. The boy agreed. He crossed the bridge, stopped to count his money and, and sure enough, it had doubled. He paid the devil $24 and crossed again. Again his money doubled. He paid another $24 and crossed a third time. Again his money had doubled, but this time there was only $24 left which he had to pay the devil so he was left with nothing. The devil laughed and vanished.  How much money did the boy start with?
Answered by Penny Nom. 





Repeating decimal notation 
20001231 

From Clarende Duby: I have seen single repeating decimals for ex. 1/3 = 0.3 with the dot above the 3 to represent the repeating decimal. Then, there is the more common form of the bar over the top of the repeating number or group of numbers (called the period?). Which notation is correct? Answered by Penny Nom. 





Bar graphs and histograms 
20000111 

From Raeluck: What is the difference between a bar graph and a histogram? Answered by Harley Weston. 





Repeating decimals 
19960909 

From Alice: What is the line called that is placed over the decimal to show that it is infinitely repeating? Answered by The Centralizer. 

