Find all School-related info fast with the new School-Specific MBA Forum

It is currently 27 Mar 2015, 18:02

Close

GMAT Club Daily Prep

Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History

Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

In the figure above, equilateral triangle ABC is inscribed

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
2 KUDOS received
Manager
Manager
avatar
Joined: 03 Jun 2010
Posts: 183
Location: United States (MI)
Concentration: Marketing, General Management
WE: Business Development (Consumer Products)
Followers: 4

Kudos [?]: 29 [2] , given: 40

GMAT ToolKit User
In the figure above, equilateral triangle ABC is inscribed [#permalink] New post 17 Jul 2010, 09:33
2
This post received
KUDOS
6
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

64% (02:09) correct 36% (01:17) wrong based on 233 sessions
Attachment:
Circle.JPG
Circle.JPG [ 5.57 KiB | Viewed 10853 times ]
In the figure above, equilateral triangle ABC is inscribed in the circle. If the length of arc ABC is 24, what is the approximate diameter of the circle?

A. 5
B. 8
C. 11
D. 15
E. 19
[Reveal] Spoiler: OA

Last edited by Bunuel on 18 Oct 2012, 09:13, edited 2 times in total.
Renamed the topic and edited the question.
Expert Post
4 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 26554
Followers: 4069

Kudos [?]: 38495 [4] , given: 4963

Re: Geometry: circle & triangle from mba.com [#permalink] New post 17 Jul 2010, 10:02
4
This post received
KUDOS
Expert's post
4
This post was
BOOKMARKED
Image
In the figure above, equilateral triangle ABC is inscribed in the circle. If the length of arc ABC is 24, what is the approximate diameter of the circle?

A. 5
B. 8
C. 11
D. 15
E. 19

Arc ABC is \frac{2}{3} of the circumference (as ABC is equilateral triangle and thus arc AB=arc BC=arc AC, so arc AB+arc BC=arc ABC = 2/3 of circumference) --> 24=c*\frac{2}{3}, hence circumference c=\frac{24*3}{2}=36=\pi{d} --> d\approx{11.5}.

Answer: C.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

GMAT Club Premium Membership - big benefits and savings

Manager
Manager
avatar
Joined: 24 Jan 2010
Posts: 164
Location: India
Schools: ISB
Followers: 2

Kudos [?]: 28 [0], given: 14

Re: Geometry: circle & triangle from mba.com [#permalink] New post 21 Jul 2010, 09:18
Bunuel wrote:
An equilateral triangle ABC is inscribed in the circle. If the length of arc ABC is 24, what is the approximate diameter of the circle?

Arc ABC is \frac{2}{3} of the circumference (as ABC is equilateral triangle and thus arc AB=arc BC=arc AC, so arc AB+arc BC=arc ABC = 2/3 of circumference) --> 24=c*\frac{2}{3}, hence circumference c=\frac{24*3}{2}=36=\pi{d} --> d\approx{11.5}.

Answer: C.


Thanks Bunuel for the explanation. Is there any other way to solve this type of questions?

Thanks in advance.
_________________

_________________
If you like my post, consider giving me a kudos. THANKS!

Manager
Manager
avatar
Status: Last few days....Have pressed the throttle
Joined: 20 Jun 2010
Posts: 71
WE 1: 6 years - Consulting
Followers: 3

Kudos [?]: 28 [0], given: 27

Re: Geometry: circle & triangle from mba.com [#permalink] New post 25 Aug 2010, 19:30
Another approach could be as follows:

Angle C subtends AB arc and angle A subtends BC arc. That means Angle C+ angle A subtends an arc of 24

120 degrees subtends arc of length 24 (since equilteral triangle so one angle = 60)
so 180 degrees subtends 36 (full circular arc or circumference)

2 pi r = 36

Diameter = 36*7/22 = 11.5 (Ans - C)
_________________

Consider giving Kudos if my post helps in some way

1 KUDOS received
Intern
Intern
avatar
Joined: 13 Aug 2010
Posts: 2
Followers: 0

Kudos [?]: 1 [1] , given: 10

Re: Geometry: circle & triangle from mba.com [#permalink] New post 08 Sep 2010, 06:28
1
This post received
KUDOS
Not exactly a scientific method, but I figured it out like this:

Triangle ABC = 24, and is an equilateral, so each side is 8. Since AB = 8, and does not go across the radius, the circumference of the circle is greater than 8. So you can then eliminate answer choices A and B. You are left with C (11), D (15) and E (19). Answer choice D, 15, is almost twice the length of AB. That almost certainly makes it too large of a number - thus you can rule out D and E. And you are left with C.

Again, not a very scientific method, but that's how I figured it out in my head in a few seconds.
Expert Post
1 KUDOS received
Veritas Prep GMAT Instructor
User avatar
Joined: 16 Oct 2010
Posts: 5352
Location: Pune, India
Followers: 1298

Kudos [?]: 6500 [1] , given: 174

Re: Geometry: circle & triangle from mba.com [#permalink] New post 18 Nov 2010, 19:15
1
This post received
KUDOS
Expert's post
prashantbacchewar wrote:
It is strange that GMAT is asking for such approximation and calculations


Actually Prashant, you don't need to calculate at all. You see that 2/3rd of circumference is 24, so the circumference of the circle must be 36.
The question asks for 2r and we know 2 pi r = 36. So 2r = 36/pi
We know pi = 3.14
Answer = 36/(3.14)
When I divide 36 by 3, I get 12 so my answer has to be less than 12.
When I divide 36 by 4, I get 9 so my answer has to more than 9. It will be closer to 12 than 9. Only possible answer is 11.

I remember, when I took GMAT, I almost never had to put the marker to the scratch pad for calculations. May be to make a little diagram, may be to make an equation to satisfy myself...
_________________

Karishma
Veritas Prep | GMAT Instructor
My Blog

Veritas Prep GMAT course is coming to India. Enroll in our weeklong Immersion Course that starts March 29!

Veritas Prep Reviews

Senior Manager
Senior Manager
avatar
Joined: 25 May 2010
Posts: 321
Location: United States
Concentration: Strategy, Finance
Schools: CBS '14 (A)
GMAT 1: 590 Q47 V25
GMAT 2: 560 Q47 V20
GMAT 3: 600 Q47 V25
GMAT 4: 680 Q49 V34
Followers: 4

Kudos [?]: 48 [0], given: 32

GMAT ToolKit User Reviews Badge
Re: Geometry: circle & triangle from mba.com [#permalink] New post 19 Nov 2010, 11:50
Pi*D=24(3/2)
This gives us approximately 11. So answer should be C.
_________________

"Whether You Think You Can or Can't, You're Right"--Henry Ford
680 Debrief
600 Debrief
590 Debrief
My GMAT Journey

2 KUDOS received
Intern
Intern
avatar
Joined: 07 Sep 2010
Posts: 18
Followers: 0

Kudos [?]: 3 [2] , given: 3

Re: Geometry: circle & triangle from mba.com [#permalink] New post 20 Nov 2010, 01:51
2
This post received
KUDOS
Let centre be denoted as O. Draw lines OA & OC. Now Angle ABC=60(equilateral triangle) & hence Angle AOC=120.
Length of the arc ABC = (x /360) * circumference, where x = 240 (ext. angle of O)
24 = (240/360)* 2 pi r
D = (36*7)/22 = 11.14 (approx.)


COUNTER ARGUMENTS WELCOME, SORRY I CUDN'T ATTACH PICTURE
SVP
SVP
avatar
Joined: 16 Nov 2010
Posts: 1688
Location: United States (IN)
Concentration: Strategy, Technology
Followers: 31

Kudos [?]: 335 [0], given: 36

Premium Member Reviews Badge
Re: Geometry: circle & triangle from mba.com [#permalink] New post 19 Apr 2011, 18:08
(120+ 120)/360 = 24/pi*d (because Angle subtended by Arc AB at Center + Angle subtended by Arc BC at Center = 2*60 + 2*60)

pi*d = 3 * 24/2

d = 36/3.14 ~ 11.something

Answer - C
_________________

Formula of Life -> Achievement/Potential = k * Happiness (where k is a constant)

GMAT Club Premium Membership - big benefits and savings

Manager
Manager
avatar
Joined: 14 Dec 2012
Posts: 85
Location: United States
Followers: 1

Kudos [?]: 14 [0], given: 186

Re: Geometry: circle & triangle from mba.com [#permalink] New post 10 May 2013, 14:40
Bunuel wrote:
Image
In the figure above, equilateral triangle ABC is inscribed in the circle. If the length of arc ABC is 24, what is the approximate diameter of the circle?

A. 5
B. 8
C. 11
D. 15
E. 19

Arc ABC is \frac{2}{3} of the circumference (as ABC is equilateral triangle and thus arc AB=arc BC=arc AC, so arc AB+arc BC=arc ABC = 2/3 of circumference) --> 24=c*\frac{2}{3}, hence circumference c=\frac{24*3}{2}=36=\pi{d} --> d\approx{11.5}.

Answer: C.

Hi Bunuel,
Can you please explain the 2/3 of circumference part? how do u derive this?
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 26554
Followers: 4069

Kudos [?]: 38495 [0], given: 4963

Re: Geometry: circle & triangle from mba.com [#permalink] New post 11 May 2013, 02:21
Expert's post
up4gmat wrote:
Bunuel wrote:
Image
In the figure above, equilateral triangle ABC is inscribed in the circle. If the length of arc ABC is 24, what is the approximate diameter of the circle?

A. 5
B. 8
C. 11
D. 15
E. 19

Arc ABC is \frac{2}{3} of the circumference (as ABC is equilateral triangle and thus arc AB=arc BC=arc AC, so arc AB+arc BC=arc ABC = 2/3 of circumference) --> 24=c*\frac{2}{3}, hence circumference c=\frac{24*3}{2}=36=\pi{d} --> d\approx{11.5}.

Answer: C.

Hi Bunuel,
Can you please explain the 2/3 of circumference part? how do u derive this?


Sure. Triangle ABC is equilateral, thus minor arcs AC, AB, and BC are equal and each is 1/3rd of the circumference (since these 3 arcs make the whole circumference). From which it follows that arc ABC is 1/3+1/3=2/3 of the circumference.

Hope it's clear.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

GMAT Club Premium Membership - big benefits and savings

Manager
Manager
avatar
Joined: 14 Dec 2012
Posts: 85
Location: United States
Followers: 1

Kudos [?]: 14 [0], given: 186

Re: Geometry: circle & triangle from mba.com [#permalink] New post 11 May 2013, 09:08
Bunuel wrote:
up4gmat wrote:
Bunuel wrote:
Image
In the figure above, equilateral triangle ABC is inscribed in the circle. If the length of arc ABC is 24, what is the approximate diameter of the circle?

A. 5
B. 8
C. 11
D. 15
E. 19

Arc ABC is \frac{2}{3} of the circumference (as ABC is equilateral triangle and thus arc AB=arc BC=arc AC, so arc AB+arc BC=arc ABC = 2/3 of circumference) --> 24=c*\frac{2}{3}, hence circumference c=\frac{24*3}{2}=36=\pi{d} --> d\approx{11.5}.

Answer: C.

Hi Bunuel,
Can you please explain the 2/3 of circumference part? how do u derive this?




Sure. Triangle ABC is equilateral, thus minor arcs AC, AB, and BC are equal and each is 1/3rd of the circumference (since these 3 arcs make the whole circumference). From which it follows that arc ABC is 1/3+1/3=2/3 of the circumference.

Hope it's clear.


yes,i got it : is it that we measure the arc length from centre of circle : (120/360)* c = c/3.. thanks bunuel!
GMAT Club Legend
GMAT Club Legend
User avatar
Joined: 09 Sep 2013
Posts: 4391
Followers: 271

Kudos [?]: 51 [0], given: 0

Premium Member
Re: In the figure above, equilateral triangle ABC is inscribed [#permalink] New post 22 Jul 2014, 20:30
Hello from the GMAT Club BumpBot!

Thanks to another GMAT Club member, I have just discovered this valuable topic, yet it had no discussion for over a year. I am now bumping it up - doing my job. I think you may find it valuable (esp those replies with Kudos).

Want to see all other topics I dig out? Follow me (click follow button on profile). You will receive a summary of all topics I bump in your profile area as well as via email.
_________________

GMAT Books | GMAT Club Tests | Best Prices on GMAT Courses | GMAT Mobile App | Math Resources | Verbal Resources

Director
Director
avatar
Joined: 26 Aug 2014
Posts: 784
Concentration: Marketing
GMAT 1: 680 Q V
GPA: 3.4
Followers: 5

Kudos [?]: 137 [0], given: 85

Re: In the figure above, equilateral triangle ABC is inscribed [#permalink] New post 26 Oct 2014, 09:10
funny how we all learn differently. I see now the "correct" way to approach this problem. For some reason when I did the test, it didn't register that AB, BC & AC arcs where also equal - I was too focused on the triangle inside and didn't see how knowing anything about the circumference would help me as I didn't have a radius. Here is what I did (might help folks that get stuck on these types of problems make good guesses.)

I said, since ABC is almost the entire circumference of the circle we can assume
piD>24 (ie entire circumference is greater than 24)
d> 24/3.14
d> 8

I knew ABC was almost the whole circle, so picked the closest number bigger which was 11.
Intern
Intern
avatar
Joined: 12 Dec 2013
Posts: 20
Followers: 1

Kudos [?]: 4 [0], given: 34

Re: In the figure above, equilateral triangle ABC is inscribed [#permalink] New post 31 Oct 2014, 23:15
Hi Bunuel,

I was trying to approach this problem with the formula R=sqrt of 3/3 * (side) and then find the diameter. Eventually got it wrong. Is there a possibility to solve this question using this formula?
Also Bunuel, could you shed some light on this approach - what sort of problems can be solved using this formula?

Thanks a bunch!
RCA
Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 26554
Followers: 4069

Kudos [?]: 38495 [0], given: 4963

Re: In the figure above, equilateral triangle ABC is inscribed [#permalink] New post 01 Nov 2014, 03:57
Expert's post
Rca wrote:
Hi Bunuel,

I was trying to approach this problem with the formula R=sqrt of 3/3 * (side) and then find the diameter. Eventually got it wrong. Is there a possibility to solve this question using this formula?
Also Bunuel, could you shed some light on this approach - what sort of problems can be solved using this formula?

Thanks a bunch!
RCA


This formula links the radius of the circumscribed circle to the side of equilateral triangle inscribed in it: R=side*\frac{\sqrt{3}}{3}. We don;t know the side, so this is not a good formula to apply here.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

GMAT Club Premium Membership - big benefits and savings

Manager
Manager
User avatar
Joined: 20 Jan 2014
Posts: 162
Location: India
GMAT Date: 10-13-2014
Followers: 0

Kudos [?]: 7 [0], given: 120

GMAT ToolKit User
Re: In the figure above, equilateral triangle ABC is inscribed [#permalink] New post 20 Dec 2014, 23:29
Whats wrong in this approach??

As it is equilateral triangle - So all angles are 60 degree.
We know that angle at the center is twice the angle made at circumference. , so angle at centre = 120 degree.

Length of arc = n/360 * 2 pi R = 120/360 * Pi * R =24 => (1/3)*3.14 * R = 24, but by this calculation R is coming approx 24 :(

Can you please tell that where i am wrong
_________________

Consider +1 Kudos Please :)

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 26554
Followers: 4069

Kudos [?]: 38495 [0], given: 4963

Re: In the figure above, equilateral triangle ABC is inscribed [#permalink] New post 21 Dec 2014, 03:43
Expert's post
him1985 wrote:
Whats wrong in this approach??

As it is equilateral triangle - So all angles are 60 degree.
We know that angle at the center is twice the angle made at circumference. , so angle at centre = 120 degree.

Length of arc = n/360 * 2 pi R = 120/360 * Pi * R =24 => (1/3)*3.14 * R = 24, but by this calculation R is coming approx 24 :(

Can you please tell that where i am wrong


The central angle of the arc ABC is 120 + 120 = 240 degrees.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

GMAT Club Premium Membership - big benefits and savings

Manager
Manager
User avatar
Joined: 20 Jan 2014
Posts: 162
Location: India
GMAT Date: 10-13-2014
Followers: 0

Kudos [?]: 7 [0], given: 120

GMAT ToolKit User
Re: In the figure above, equilateral triangle ABC is inscribed [#permalink] New post 21 Dec 2014, 05:45
Bunuel wrote:
him1985 wrote:
Whats wrong in this approach??

As it is equilateral triangle - So all angles are 60 degree.
We know that angle at the center is twice the angle made at circumference. , so angle at centre = 120 degree.

Length of arc = n/360 * 2 pi R = 120/360 * Pi * R =24 => (1/3)*3.14 * R = 24, but by this calculation R is coming approx 24 :(

Can you please tell that where i am wrong


The central angle of the arc ABC is 120 + 120 = 240 degrees.


I still can not understand how it becomes 240+240 . I have attached the figure.
Can you please clear my doubt.
Attachments

Ques.png
Ques.png [ 11.56 KiB | Viewed 1294 times ]


_________________

Consider +1 Kudos Please :)

Expert Post
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 26554
Followers: 4069

Kudos [?]: 38495 [0], given: 4963

Re: In the figure above, equilateral triangle ABC is inscribed [#permalink] New post 21 Dec 2014, 07:44
Expert's post
him1985 wrote:
Bunuel wrote:
him1985 wrote:
Whats wrong in this approach??

As it is equilateral triangle - So all angles are 60 degree.
We know that angle at the center is twice the angle made at circumference. , so angle at centre = 120 degree.

Length of arc = n/360 * 2 pi R = 120/360 * Pi * R =24 => (1/3)*3.14 * R = 24, but by this calculation R is coming approx 24 :(

Can you please tell that where i am wrong


The central angle of the arc ABC is 120 + 120 = 240 degrees.


I still can not understand how it becomes 240+240 . I have attached the figure.
Can you please clear my doubt.


Attachment:
Untitled.png
Untitled.png [ 12.63 KiB | Viewed 1276 times ]
The red arc is 24 and its central angle is 240 degrees.

Hope it's clear.
_________________

NEW TO MATH FORUM? PLEASE READ THIS: ALL YOU NEED FOR QUANT!!!

PLEASE READ AND FOLLOW: 11 Rules for Posting!!!

RESOURCES: [GMAT MATH BOOK]; 1. Triangles; 2. Polygons; 3. Coordinate Geometry; 4. Factorials; 5. Circles; 6. Number Theory; 7. Remainders; 8. Overlapping Sets; 9. PDF of Math Book; 10. Remainders; 11. GMAT Prep Software Analysis NEW!!!; 12. SEVEN SAMURAI OF 2012 (BEST DISCUSSIONS) NEW!!!; 12. Tricky questions from previous years. NEW!!!;

COLLECTION OF QUESTIONS:
PS: 1. Tough and Tricky questions; 2. Hard questions; 3. Hard questions part 2; 4. Standard deviation; 5. Tough Problem Solving Questions With Solutions; 6. Probability and Combinations Questions With Solutions; 7 Tough and tricky exponents and roots questions; 8 12 Easy Pieces (or not?); 9 Bakers' Dozen; 10 Algebra set. ,11 Mixed Questions, 12 Fresh Meat

DS: 1. DS tough questions; 2. DS tough questions part 2; 3. DS tough questions part 3; 4. DS Standard deviation; 5. Inequalities; 6. 700+ GMAT Data Sufficiency Questions With Explanations; 7 Tough and tricky exponents and roots questions; 8 The Discreet Charm of the DS ; 9 Devil's Dozen!!!; 10 Number Properties set., 11 New DS set.


What are GMAT Club Tests?
25 extra-hard Quant Tests

GMAT Club Premium Membership - big benefits and savings

Re: In the figure above, equilateral triangle ABC is inscribed   [#permalink] 21 Dec 2014, 07:44

Go to page    1   2    Next  [ 22 posts ] 

    Similar topics Author Replies Last post
Similar
Topics:
17 Experts publish their posts in the topic In the figure above, triangle ABC is equilateral, and point Walkabout 16 03 Dec 2012, 03:36
6 Experts publish their posts in the topic In the figure above, equilateral triangle ABC is inscribed i bmiller0731 17 02 Mar 2009, 08:50
9 Experts publish their posts in the topic The triangles in the figure above are equilateral and the jimmylow 10 05 Apr 2008, 21:14
A circle is inscribed in equilateral triangle ABC such that usman7 6 01 Oct 2006, 10:43
16 Experts publish their posts in the topic In the figure above, equilateral triangle ABC is inscribed Folaa3 5 20 Aug 2005, 14:44
Display posts from previous: Sort by

In the figure above, equilateral triangle ABC is inscribed

  Question banks Downloads My Bookmarks Reviews Important topics  


cron

GMAT Club MBA Forum Home| About| Privacy Policy| Terms and Conditions| GMAT Club Rules| Contact| Sitemap

Powered by phpBB © phpBB Group and phpBB SEO

Kindly note that the GMAT® test is a registered trademark of the Graduate Management Admission Council®, and this site has neither been reviewed nor endorsed by GMAC®.