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Running around a circular track 2020-10-31
From kaylee:
Keiko and Kendra are training for an international track competition. Kendra is running one lap on the outside of a circular track with a diameter of 1000 feet. Her constant rate of speed is 12 mi/h. Keiko is running one lap on the outside of a nearby circular track with a diameter of 1125 feet. She is also running at 12 mi/h. Find the time, in minutes, each runner needs to complete one lap.
Answered by Harley Weston.
A circle with a circular hole 2019-03-11
From Sue:
My little one is wondering if a circle with a circular hole could be described as an irregular semicircle.
As it has 2 sides but is not the standard shape. Could you share your thoughts ??

Answered by Penny Nom.
Running around a circular track in opposite directions 2019-02-24
From carmi:
how many times will lita and rose pass each other in 15 minutes if lita and rose start jogging on a 110 meters circular track. they begin at the same point but in opposite direction. lita at 8/3 meters per second and rose at 7/3 meters per second.
Answered by Penny Nom.
Two cones formed from two circular sectors 2018-11-30
The central angles of two sector of a circle are 60 and 120 . Using these sectors two cones are made. If the radius of the smaller cone is 5 cm, find the radius and base area of the larger cone.
Answered by Penny Nom.
Amy and Joey on a circular track 2018-08-13
From Zoe:
Amy and Joey are situated on a circular track 400 feet around.
Joey starts running at a rate of 10 feet per second.
Amy waits for a full minute, then starts running from the same point (in the same direction) at 12 feet per second.

How many seconds elapse before Amy passes Joey on the track?

Answered by Penny Nom.
The base for a circular pool 2018-06-10
From Adam:
How many sheet of 4ft by 8ft foam would I need to lay under a pool 15dt in diameter
Answered by Penny Nom.
A cone formed from a circular sector 2018-04-18
From Jessica:
A circle has a radius of 7.5cm. A sector with an angle of 240 degrees is cut out from the sector. If the sector is folded to form a cone. Find the length of the cone.
Answered by Penny Nom.
An arched window 2017-07-24
From Gerry:
Looking to make a full size template for an arched window. Need increments every 16". The radius is 138' 0 9/16" , the chord is 226" and the rise at center of chord is 43"
Answered by Penny Nom.
The volume of a slab 2017-01-21
From Russell:
Working with a segment of a circle. The O.D. is 3.440" the length of the chord is 3.130 I need information on the volume of the largest area. I would like to know (in thousands of an inch) how tall would the largest area need to be to equal .1143 cubic inches If you need more info I can send it Thanks in advance
Answered by p.
Heights at various points along an arc 2016-04-15
From Isiah:
So I am working on a problem with a few friends; you have an arc with the center of its chord at 0,0. We also have a known sagitta and a known radius of curvature. How do we calculate the height extending in both the positive and negative directions?
Central sag: 2.48
Chord length: 9.6

Answered by Penny Nom.
Archimedes, Euclid and "Circular Reasoning" 2015-11-15
From Ron:
I have read about Archimedes and his work with sphere in cylinder and cone in cylinder and the volume relationships. Did he or any others also extend this to regular based polygon based regular like pillars, and columns? The ratio of 1/3 to 1 whole holds true with all regular based columns as example: a regular pyramid having a regular hexagon base inside a regular hexagon column of equal height.
Answered by Chris Fisher.
The area of a domed roof 2015-11-13
From Brandon:
I have a tank with a 13' radius that has a domed roof of 3.5' tall How do I figure out the area in SQFT?
Answered by Penny Nom.
Reinforced steel mesh in a circular foundation 2015-08-22
From Padmesh:
in a circular foundation we are laying a reinforced steel mesh . i.e., like chords in both ways. the circle diameter is 2.91m and rods are placed 0.1m spacing. so I want to find the number of rods present in that circle. here by I am attaching an auto cad drawing for your reference
Answered by Penny Nom.
The surface area of a round bar 2015-06-06
From chirag:
Please tell me the formula for finding round bar surface in square inches/ mm
Answered by Penny Nom.
A parallelogram inscribed in a circle 2015-02-04
From narendra:
how can we prove that a circular parallelogram is a rectangle?
Answered by Chris Fisher.
The surface area of a circular dome 2014-04-10
From Shafiqah:
Is this a dome's surface area formula??
{{2 π r h square units}}
Is the surface area of the floor for the dome is calculate too in this formula?

Thanks for answering. =)

Answered by Robert Dawson and Penny Nom.
Can a cylinder be considered a circular prism? 2014-02-08
From Davina:
Can a cylinder be considered a circular prism?
Answered by Penny Nom.
A square inscribed in a circle 2013-10-14
From Jenn:
Hello! I am about to buy a 7'9" round rug, but I want to have it cut down into a square. What's the largest square I can obtain from this? Thank you!
Answered by Penny Nom.
A semi-circular roof gutter 2012-04-09
From Kyle:
A semi-circular roof guttering contains some water.
The cross-section of the guttering has a diameter of 10 centimetres. The surface of the water collected in the guttering is 8cm. What is the depth of water in the gutter?

Answered by Penny Nom.
A man made circular lake 2010-11-25
From ailish:
A man made circular lake has a diameter of 338 m. A bridge is to be constructed across the lake in such a way that it is 119 m away from the center of the lake. How long is the bridge?
Answered by Penny Nom.
May Lee's cake 2010-09-18
From Wafa:
May Lee bought a cake which is circular in shape. Her sister ate a quarter of the cake. Given that the area of the top surface of the remaining portion is 520 square cm, find the diameter of the cake.
Answered by Penny Nom.
Two cars on a circular track 2010-08-12
From david:
If two cars starts to drive at point 1 and go in a circle when will they meet? (one cars speed is faster the other ) all I need is a formula
Answered by Tyler Wood.
A pile of sand 2009-12-16
From Malik:
Sand is leaking out of a hole at the bottom of a container at a rate of 90cm3/min. As it leaks out, it forms a pile in the shape of a right circular cone whose base is 30cm below the bottom of the container. The base radius is increasing at a rate of 6mm/min. If, at the instant that 600cm3 have leaked out, the radius is 12cm, find the amount of leakage when the pile touches the bottom of the container.
Answered by Harley Weston.
A circular border around a pool 2009-09-08
From Calvin:
A pool in the shape of a circle measures 10 feet across. One cubic yard of concrete is to be used to create a circular border of uniform width around the pool. If the border is to have a depth of 3 inches, how wide will the border be? ( 1 cubic yard=27 cubic feet )
Answered by Stephen La Rocque.
4 couples seating themselves at a round table 2009-09-04
From Hui:
Q: 4 couples seating themselves at a round table. Men must seat together and women seat together. How many ways are there? Answer in the printed text is 576. I got 144. Pls advice.
Answered by Claude Tardif.
The surface area of a tank 2009-06-25
From Charles:
I need to calculate the external wall and top sqft surface area of a tank 54ft od x 15ft high with a dome top 54ft od x 8ft high.
Answered by Penny Nom.
A semi circular room 2009-02-11
From Taylor:
being 450pi (the area of a semi circle)

how much money would it cost to lay carpet at $2.57 per foot???

if the area of a semi circular room is 450 pi ft then what is the volume being that the diameter is 60 feet and the ceiling is 16 feet tall

Answered by Robert Dawson and Penny Nom.
Seating around a circular table 2009-02-09
From Jenny:
A committee of 15 -- 9 women and 6 men -- is to be seated at a circular table (with 15 seats). In how many ways can the seats be assigned so that no two men are seated next to each other?
Answered by Victoria West.
Three circular rings 2008-12-18
From seema:
three circular rings of equal radii of 1cm each are touching each other. a string runs all around the set of rings very tightly. what is the minimum length of string required to bind all the three rings ?
Answered by Robert Dawson.
Jogging around a circular track 2008-11-19
From kim:
Joan wants to jog 10 miles on a circular track 1/4 miles in diameter. How many times must she circle the track?
Answered by Penny Nom.
The volume of fluid in a semi circular trough 2008-10-10
From Kerry:
How do I find the volume of fluid in a semi circular trough?
Answered by Penny Nom.
A bowl is the shape of a hemisphere 2008-04-28
From josh:
a bowl is the shape of a hemisphere with diameter 30 cm and water is poured into the bowl to a height h cm. how do i find the volume of the water in the bowl
Answered by Harley Weston.
The radius of a circular arc 2008-02-04
From Bill:
Hi,the Central Angle of a sector of a circle is 40 degrees. The circular arc of the curve has a chord length of 3000 ft. Find the radius(r) of the circular arc.
Answered by Penny Nom.
A large concrete shape 2008-01-16
From Keith:
what is the cubic yards of an area that is not a perfect 1/4 circle? The dimensions are 100ft. x 60ft. x 125ft. curcumferal arch x 3ft. depth?
Answered by Stephen La Rocque.
An arched entry 2007-11-28
From amber:
i am working with an arched entry. i know that the radius is 25' and the height is 20'-11". i need to know the length of the arch and degree of bend of the arch. how do i find these?
Answered by Stephen La Rocque.
A circular table is pushed into the corner 2007-10-31
From Will:
A circular table is pushed into the corner of a square room so that one point is 8 inches from one wall and 9 inches from the other. What is the radius of the table?
Answered by Penny Nom.
A cylindrical slab of concrete 2007-06-30
From Kenn:
I have a tank that needs a base of cement put in it. I dont know how to do this. The tank is 8 feet across and I want the cement to be 5 or 6 inches deep. Can you please tell me how much cement I need to do this.
Answered by Harley Weston.
Water tank volume 2007-05-29
From Cecelia:
Answered by Stephen La Rocque.
Constructing an octagonal deck around a circular pool 2007-04-20
From Cliff:
[I am building an] octagonal desk encompassing 17 foot diameter circle for pool. I have seen other octagonal calculations but none of these tell me how much allowance for a circle to fit within the octagon without losing the circle edge can anyone help thanks cliff
Answered by Stephen La Rocque.
How many feet tall is the tunnel 2006-10-14
From Charles:
A tunnel in the Smoky Mountains is semicircular. At a distance of 12 feet from the center of the tunnel, the tunnel has a height of 16 feet. How many feet tall is the tunnel at its center?
Answered by Penny Nom.
Gallons of water in a well 2006-07-31
From Martha:
I have a shallow water well that is 30 feet in depth.

I have 8 feet of water in the well.

The water well is a 30 inch in diameter.

My question : How many gallons of water is in my tank?

Answered by Penny Nom.
A cone with vertex (1,1,2) 2005-09-26
From Brandon:
Find the equation of a double cone with vertex (1,1,2) and which intersects the xy plane in a circle of radius 4.
Answered by Penny Nom.
A seating arrangement 2005-02-03
From Kay:
If you have 5 married couples, how many arrangements can be made if they must sit across from each other?
Answered by Penny Nom.
A line from the center of the patch to the periphery 2005-01-01
From Sandrine:
I am currently researching a patch disease of grasses. These patches are roughly circular. I need a term for a line from the center of the patch to the periphery. Since the patches are not perfectly circular, my supervisors tell me I cannot use the word 'radius'. What else could I use?
Answered by Denis Hanson and Harley Weston.
Volume of a fuel tank 2004-03-01
From Mike:
I have a fuel ank for my big truck that has a radius of 24inches and a length of 65 inches. I am trying to compute the volume of fuel in the tank. I tried pie x the radius squared times the length but no usable results. Can you help me please?
Answered by Penny Nom.
Volume of a tube 2004-01-14
From Mike:
where can you find how to get volume of a tube: 3 in across x 3 inch high
5 in across x 5 inch high
same formula for both. ONE will get the other.

Answered by Penny Nom.
Arrangements around a circular table 2003-10-07
From Lori:
How many arrangements can 6 people be seated round a circular table?
Answered by Penny Nom.
The volume of water in a hose 2002-11-13
From David:
I trying to find out how much water 500 ft of 3/4 inch hose will hold. I'd also like to know how you figured the answer.
Answered by Penny Nom.
A circular wading pool 2002-03-04
From Patrick:
The community of melfort is planning to build a circular wading pool in the park. The pool will cover an area of 1000m2. The building committee has decided to put a 5m cement pad around it. How much additional area will the cement pad take up?
Answered by Harley Weston.
Building a circular silo 2001-01-24
From Natasha:
We wish to build a circular silo with internal diameter 10 feet. How much concrete will we need to pour the foundation, if we only need a 1 foot wide and 1 foot deep ring on which the silo walls will sit? Assume the 4 inch thick silo wall rests on the middle of the ring.
Answered by Penny Nom.
Circular Permutations 2000-09-18
From J. Stuart:
I am able to understand the simple theory behind circular permutations (that is, there are (n-1)! ways to arrange n people in a circle. One question, however, is giving me some difficulty. It reads: In how many ways can four married couples be arranged around a circular table if each man must sit beside his wife? Any suggestions you have would be greatly appreaciated.
Answered by Penny Nom.
Trolls and Gargoyles 1999-11-02
From TexGrimm:
How can you seat 6 monsters - 3 Trolls and 3 Gargoyles- at a circular table if the trolls look alike and the gargoyles look alike? Does your formula work for 9 monsters - 4 trolls and 5 gargoyles?
Answered by Penny Nom.
Circular Permutations 1997-02-05
From Ed Varjassy:
I have an understanding of simple problems involving circular permutations but do not understand them when they start to have restrictions. Is there any advice you can give for these more complicated permutations.
Answered by Penny Nom.



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