Previous in Forum: What's up Doc?   Next in Forum: Simple Algebra Problem?
Close
Close
Close
19 comments
Rate Comments: Nested
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1851
Good Answers: 65

Formula for Common Area of Intersecting Circles

08/05/2009 10:55 AM

What is the formula for the common area when 2 circles

of Radius R and r is intersecting each other where 0<x< R-r

where x is the common ordinate for 2 circles.

DHAYANANDHAN.S,

INDIA

Register to Reply
Interested in this topic? By joining CR4 you can "subscribe" to
this discussion and receive notification when new comments are added.

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Guru
Popular Science - Biology - New Member Hobbies - Musician - New Member APIX Pilot Plant Design Project - Member - New Member Hobbies - CNC - New Member Fans of Old Computers - ZX-81 - New Member

Join Date: Jan 2007
Location: Centurion, South Africa
Posts: 3921
Good Answers: 97
#1

Re: FORMULA FOR COMMON AREA OF 2 INTERSECTING CIRCLES OF RADIUS R and r.

08/05/2009 11:34 AM

The area of a sector = R² * cos ¨¹ (R - H) - (R-H) √ 2Rh - H²

Where H = distance centre to x line - R.

add the same for r

After relaring h and H to the distance between centres.

__________________
Never do today what you can put of until tomorrow - Student motto
Register to Reply Score 1 for Good Answer
Guru
Engineering Fields - Manufacturing Engineering - New Member Hobbies - Target Shooting - New Member United States - Member - New Member Hobbies - Hunting - New Member

Join Date: Dec 2006
Location: Charlotte, NC USA
Posts: 791
Good Answers: 17
#2

Re: Formula for Common Area of 2 Intersecting Circles of Radius R and r

08/05/2009 1:24 PM

That has to be a homework question...

__________________
Be careful of what you wish for .....
Register to Reply
Guru
Popular Science - Biology - New Member Hobbies - Musician - New Member APIX Pilot Plant Design Project - Member - New Member Hobbies - CNC - New Member Fans of Old Computers - ZX-81 - New Member

Join Date: Jan 2007
Location: Centurion, South Africa
Posts: 3921
Good Answers: 97
#3

Re: Formula for Common Area of Intersecting Circles

08/05/2009 1:50 PM

hi

I used the wrong word, it should have been segment

the area of the sector (wedge) = 1/2 R²Θ = 1/2 R * s

where s = R Θ

and the A segment = A wedge/sector - A triangle

__________________
Never do today what you can put of until tomorrow - Student motto
Register to Reply
3
Guru
India - Member - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Oct 2006
Location: India, 200 Km. North of Delhi.
Posts: 1393
Good Answers: 53
#4

Re: Formula for Common Area of Intersecting Circles

08/05/2009 1:52 PM

If Understand you correct it should be like this-

Area of intersection =(a*sin-1 X/2r)/180 -Xr + (A*sin-1 X/2R)/180 -XR

a= Area of circle1

A= Area of circle2

Register to Reply Good Answer (Score 3)
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1851
Good Answers: 65
#6
In reply to #4

Re: Formula for Common Area of Intersecting Circles

08/06/2009 11:34 AM

Thank You Mr. RAKESH SEMSEMWAL for your reply.

Indeed, I should have given the sketch. However in your sketch

what you have shown dimension x to be taken in a perpendicular

way to the line. i.e horizontal way and in this way value of x will be

smaller than what you have considered. In other words, the dimension

x shown in your sketch should be taken prpendicular way to the

line shown by you in your sketch. I hope now I have made my self clear.

DHAYANANDHAN.S'

CR4 MEMBER.

Register to Reply
Guru
India - Member - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Oct 2006
Location: India, 200 Km. North of Delhi.
Posts: 1393
Good Answers: 53
#10
In reply to #6

Re: Formula for Common Area of Intersecting Circles

08/06/2009 12:41 PM

Mr.DHAYANANDHAN.S'

Thank you for your reply.

Equation still hold the validity with ref to the drawing I have made there, Only thing you will have to do is convert it to your desire.

If you feel any difficulty please don't hesitate and get back to me.

Thank you,

Regards.

Register to Reply
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1851
Good Answers: 65
#9
In reply to #4

Re: Formula for Common Area of Intersecting Circles

08/06/2009 11:44 AM

Sorry Mr. . RAKESH SEMWAL,

While replying to your quiery, your name is wrongly typed.

Sincerely REGRET and apologise for the mistake.

dhayanandhan.s,

CR 4 MEMBER.

Register to Reply
Anonymous Poster
#18
In reply to #4

Re: Formula for Common Area of Intersecting Circles

02/15/2010 4:36 PM

hi thank you ! i searched and go on thinking for many days but your information is very useful..............

Register to Reply Off Topic (Score 5)
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5826
Good Answers: 322
#5

Re: Formula for Common Area of Intersecting Circles

08/06/2009 4:16 AM

Hi dhayanandhan when you say:-

where x is the common ordinate for 2 circles.

what do you mean?

http://dictionary.die.net/ordinate

ordinate n : the value of a coordinate on the vertical axis

Maybe this:-

The point D has ordinate 2.64 which is less than (7-4).

Can you draw a picture of what you want?

Geogebra is a free package you can download, and, Screen Capture + Print is a great free screen capture utility.You cay then post the picture using the little green camera:-

__________________
If you spend all your time looking for people and things to complain about: trust me, you will find plenty to complain about.
Register to Reply
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1851
Good Answers: 65
#7
In reply to #5

Re: Formula for Common Area of Intersecting Circles

08/06/2009 11:40 AM

Thank you Mr. Randall for your reply.

The reply to Mr.SEMWAL also holds good for your quiery also.

thanks,

DHAYANANDHAN.S

CR4 MEMBER.

Register to Reply
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5826
Good Answers: 322
#11
In reply to #7

Re: Formula for Common Area of Intersecting Circles

08/06/2009 1:55 PM

Like this then?

__________________
If you spend all your time looking for people and things to complain about: trust me, you will find plenty to complain about.
Register to Reply
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1851
Good Answers: 65
#13
In reply to #11

Re: Formula for Common Area of Intersecting Circles

08/07/2009 11:32 PM

YES Mr. RANDALL,

YOU ARE RIGHT.

DHAYANANDHAN.S,

CR4 MEMBER.

Register to Reply
Anonymous Poster
#8
In reply to #5

Re: Formula for Common Area of Intersecting Circles

08/06/2009 11:43 AM

Hi Randall,

Thanks for sharing, we all will benefit from this software, I'm very bad at math, but now I will be more lazy.

I already downloaded and tried it; awesome, thanks.

Yahlasit

Register to Reply
Guru
India - Member - New Member Engineering Fields - Electromechanical Engineering - New Member

Join Date: Oct 2006
Location: India, 200 Km. North of Delhi.
Posts: 1393
Good Answers: 53
#12

Re: Formula for Common Area of Intersecting Circles

08/07/2009 6:36 AM

Mr dhayanandhan with the changed variables it should be like this

{a*Cos-1(r-x/2)/r}/180 - √(rx-x2/4)*(r-x/2) + {A*Cos-1(R-x/2)/R}/180 - √(Rx-x2/4)*(R-x/2)

a= area of circle 1

A= area of circle 2

Register to Reply
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1851
Good Answers: 65
#14
In reply to #12

Re: Formula for Common Area of Intersecting Circles

08/09/2009 6:28 AM

Dear Mr. Rakesh Semwal,

Your sketch is right, indicating the distance x

in the horizontal line. I also made a sketch

in the autocad format similarly but it is not

getting up loaded. If you send your personal

E-Mail, I can send my sketch. Now the

question from me was "what is the area of the shaded

portion of the intersecting circles, as seen in your sketch.

In deed you Mr. Randall have taken much pains.

I thank you for your response.

DHAYANANDHAN.S,

CR4 MEMBER.

Register to Reply
Anonymous Poster
#15

Re: Formula for Common Area of Intersecting Circles

10/02/2009 5:50 PM

This is a similar but I am sure simpler question, and if I were better at math, the answer is already here, I just cannot see it.

If two circles, of equal diameter intersect at each other's center,what is the length of the arc formed beginniing at the point where they first intersect, and ending at the next point of intersection.similar to the previous question, but not the area, simply the length of the curved line is desired to be known.

Thanks

Stu

Register to Reply
Guru

Join Date: Aug 2005
Location: Hemel Hempstead, UK
Posts: 5826
Good Answers: 322
#16
In reply to #15

Re: Formula for Common Area of Intersecting Circles

10/05/2009 2:01 AM

Do you mean like this:-

Then the answer is clearly 2πR/3

__________________
If you spend all your time looking for people and things to complain about: trust me, you will find plenty to complain about.
Register to Reply Off Topic (Score 5)
Guru
Engineering Fields - Mechanical Engineering - New Member

Join Date: May 2008
Location: CHENNAI, TAMIL NADU, INDIA.
Posts: 1851
Good Answers: 65
#17
In reply to #16

Re: Formula for Common Area of Intersecting Circles

10/09/2009 12:09 PM

Yes Mr. Randall,

Your 1st sketch with 2 circles is right, and x is measured in the horizontal line.

Indeed, I thank you for your response ,

sorry for the delay in replying.

dhayanandhan.s,

cr4 member

india

Register to Reply Off Topic (Score 5)
Anonymous Poster
#19

Re: Formula for Common Area of Intersecting Circles

06/18/2010 11:31 AM

This has been very helpful, but I can't seem to resolve the equation to find out what it would be if I have the area of the shaded question and want to find X.

Register to Reply
Register to Reply 19 comments

Good Answers:

These comments received enough positive votes to make them "good answers".

"Almost" Good Answers:

Check out these comments that don't yet have enough votes to be "official" good answers and, if you agree with them, vote them!
Copy to Clipboard

Users who posted comments:

Anonymous Poster (4); dhayanandhan (6); Hendrik (2); Labyguy (1); rakesh_semwal (3); Randall (3)

Previous in Forum: What's up Doc?   Next in Forum: Simple Algebra Problem?

Advertisement