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

It is currently 16 Sep 2014, 13:45

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

What is the area of circle passing points A, B & C (in the

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:
Senior Manager
Senior Manager
User avatar
Joined: 28 Mar 2012
Posts: 285
Concentration: Entrepreneurship
GMAT 1: 640 Q50 V26
GMAT 2: 660 Q50 V28
GMAT 3: 730 Q50 V38
Followers: 16

Kudos [?]: 157 [0], given: 23

GMAT ToolKit User GMAT Tests User
What is the area of circle passing points A, B & C (in the [#permalink] New post 25 Jun 2012, 08:39
1
This post was
BOOKMARKED
00:00
A
B
C
D
E

Difficulty:

  85% (hard)

Question Stats:

14% (01:25) correct 86% (00:42) wrong based on 56 sessions
What is the area of circle passing points A, B & C (in the given figure), if the angle ABC is 60?

(1) Angle AOC is 120.
(2) OA is 6 units.
Attachment:
File comment: Rough Diagram
Q.jpg
Q.jpg [ 18.97 KiB | Viewed 1384 times ]


[Reveal] Spoiler: Solution
As per the below diagram, lets say a circle is passing through AOC.
angle AOC = angle AEC, so, irrespective of the fact that O is center or not, it is possible to have any angle as twice of angle ABC.

Thus, even after combining the two statement we can't figure out whether O is center of the circle.

Remember, the angle subtended by arc at the center is twice of the angle subtended by the arc on rest of the circumference but the converse is not true.
Attachment:
A.jpg
A.jpg [ 15.11 KiB | Viewed 1154 times ]
[Reveal] Spoiler: OA

_________________

My posts: Solving Inequalities, Solving Simultaneous equations, Divisibility Rules

My story: 640 What a blunder!

Vocabulary resource: EdPrep

Facebook page: fb.com/EdPrep


Last edited by cyberjadugar on 27 Jun 2012, 03:09, edited 2 times in total.
Intern
Intern
avatar
Status: Fighting Gravity..
Joined: 25 May 2012
Posts: 29
Location: India
GMAT 1: 660 Q47 V35
GMAT 2: 750 Q50 V41
GPA: 3.25
WE: Programming (Computer Software)
Followers: 0

Kudos [?]: 10 [0], given: 6

Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 25 Jun 2012, 09:36
Both statements are required.
We need the first to prove that 'O' is the centre of the circle and second one to know the radius.
Senior Manager
Senior Manager
User avatar
Joined: 28 Mar 2012
Posts: 285
Concentration: Entrepreneurship
GMAT 1: 640 Q50 V26
GMAT 2: 660 Q50 V28
GMAT 3: 730 Q50 V38
Followers: 16

Kudos [?]: 157 [0], given: 23

GMAT ToolKit User GMAT Tests User
Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 25 Jun 2012, 18:16
ankushgrover wrote:
Both statements are required.
We need the first to prove that 'O' is the centre of the circle and second one to know the radius.

Hi,

Think about it some more!

Regards,
_________________

My posts: Solving Inequalities, Solving Simultaneous equations, Divisibility Rules

My story: 640 What a blunder!

Vocabulary resource: EdPrep

Facebook page: fb.com/EdPrep

Manager
Manager
User avatar
Status: Rising GMAT Star
Joined: 05 Jun 2012
Posts: 133
Location: Philippines
Concentration: General Management, Finance
GMAT 1: 660 Q V
GPA: 3.22
WE: Corporate Finance (Consulting)
Followers: 6

Kudos [?]: 17 [0], given: 16

Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 25 Jun 2012, 19:53
cyberjadugar wrote:
What is the area of circle passing points A, B & C (in the given figure), if the angle ABC is 60?

(1) Angle AOC is 120.
(2) OA is 6 units.


I was supposed to answer B. But that is wrong, why? Because the sufficiency of answer B is pivoted on the assumption that O is indeed the center of the circle. But, this is not the case. The question doesn't tell us that O is the center of the circle. This is a very good assumption/data sufficiency question. It doesn't necessarily mean that ABC is 60 that AOC is already 120. That'd be a wrong assumption. What is OA is an arc? or OA is a line segment not connected to the center?

Now, as like what the poster said above, we need A to prove that O is the center. Now that we know O is the center and from (2) we know that OA is 6 units, we know that the radius of the circle is 6. From that we can know the area of the circle.
_________________

Far better is it to dare mighty things, to win glorious triumphs, even though checkered by failure... than to rank with those poor spirits who neither enjoy nor suffer much, because they live in a gray twilight that knows not victory nor defeat.
- T. Roosevelt

Senior Manager
Senior Manager
User avatar
Joined: 28 Mar 2012
Posts: 285
Concentration: Entrepreneurship
GMAT 1: 640 Q50 V26
GMAT 2: 660 Q50 V28
GMAT 3: 730 Q50 V38
Followers: 16

Kudos [?]: 157 [0], given: 23

GMAT ToolKit User GMAT Tests User
Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 25 Jun 2012, 20:16
gmatsaga wrote:
cyberjadugar wrote:
What is the area of circle passing points A, B & C (in the given figure), if the angle ABC is 60?

(1) Angle AOC is 120.
(2) OA is 6 units.


I was supposed to answer B. But that is wrong, why? Because the sufficiency of answer B is pivoted on the assumption that O is indeed the center of the circle. But, this is not the case. The question doesn't tell us that O is the center of the circle. This is a very good assumption/data sufficiency question. It doesn't necessarily mean that ABC is 60 that AOC is already 120. That'd be a wrong assumption. What is OA is an arc? or OA is a line segment not connected to the center?

Now, as like what the poster said above, we need A to prove that O is the center. Now that we know O is the center and from (2) we know that OA is 6 units, we know that the radius of the circle is 6. From that we can know the area of the circle.

Hi,

Again, a little more thinking required...and I would say it's safe to assume OA is line segment.

Regards,
_________________

My posts: Solving Inequalities, Solving Simultaneous equations, Divisibility Rules

My story: 640 What a blunder!

Vocabulary resource: EdPrep

Facebook page: fb.com/EdPrep

Intern
Intern
avatar
Status: Fighting Gravity..
Joined: 25 May 2012
Posts: 29
Location: India
GMAT 1: 660 Q47 V35
GMAT 2: 750 Q50 V41
GPA: 3.25
WE: Programming (Computer Software)
Followers: 0

Kudos [?]: 10 [0], given: 6

Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 26 Jun 2012, 02:30
I would say i've thought enough and i will still go with my original answer!!

Plz provide the correct answer and explanation..

Thanks

Posted from my mobile device Image
Intern
Intern
avatar
Joined: 06 Jun 2012
Posts: 1
Followers: 0

Kudos [?]: 0 [0], given: 1

Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 26 Jun 2012, 02:36
I guess the answer is E. Taking the two statements together we get that the area of the circle is 36*pi "square units".
Manager
Manager
avatar
Joined: 02 Jun 2011
Posts: 160
Followers: 1

Kudos [?]: 23 [0], given: 11

Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 26 Jun 2012, 14:53
given information -
1.) A, B, C are on circle
2.) angle ABC = 60
area of circle = ?

St. 1) Angle AOC = 120, when Angle ABC = 60
Angle AOC is central angle BUT Not sufficient

St. 2.) OA= 6 - Not sufficient

1 + 2
OA is the radius hence area of circle = 36pi - Sufficient

Answer - C
Senior Manager
Senior Manager
User avatar
Joined: 28 Mar 2012
Posts: 285
Concentration: Entrepreneurship
GMAT 1: 640 Q50 V26
GMAT 2: 660 Q50 V28
GMAT 3: 730 Q50 V38
Followers: 16

Kudos [?]: 157 [0], given: 23

GMAT ToolKit User GMAT Tests User
Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 26 Jun 2012, 18:52
Posted the OA in the question.

Regards,
_________________

My posts: Solving Inequalities, Solving Simultaneous equations, Divisibility Rules

My story: 640 What a blunder!

Vocabulary resource: EdPrep

Facebook page: fb.com/EdPrep

Manager
Manager
User avatar
Status: Rising GMAT Star
Joined: 05 Jun 2012
Posts: 133
Location: Philippines
Concentration: General Management, Finance
GMAT 1: 660 Q V
GPA: 3.22
WE: Corporate Finance (Consulting)
Followers: 6

Kudos [?]: 17 [0], given: 16

Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 27 Jun 2012, 00:17
cyberjadugar wrote:
Posted the OA in the question.

Regards,


Can you explain why (E) is the answer?
_________________

Far better is it to dare mighty things, to win glorious triumphs, even though checkered by failure... than to rank with those poor spirits who neither enjoy nor suffer much, because they live in a gray twilight that knows not victory nor defeat.
- T. Roosevelt

1 KUDOS received
Senior Manager
Senior Manager
User avatar
Joined: 28 Mar 2012
Posts: 285
Concentration: Entrepreneurship
GMAT 1: 640 Q50 V26
GMAT 2: 660 Q50 V28
GMAT 3: 730 Q50 V38
Followers: 16

Kudos [?]: 157 [1] , given: 23

GMAT ToolKit User GMAT Tests User
Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 27 Jun 2012, 03:11
1
This post received
KUDOS
Posted the solution in the question.

Regards,
_________________

My posts: Solving Inequalities, Solving Simultaneous equations, Divisibility Rules

My story: 640 What a blunder!

Vocabulary resource: EdPrep

Facebook page: fb.com/EdPrep

Manager
Manager
avatar
Joined: 06 Feb 2013
Posts: 60
Followers: 1

Kudos [?]: 8 [0], given: 33

Re: What is the area of circle passing points A, B & C (in the [#permalink] New post 17 Sep 2013, 07:21
cyberjadugar wrote:
Posted the solution in the question.

Regards,


Good problem, though was confused by the phrase "area of circle passing points"...what is the source of the problem? Thanks!
_________________

There are times when I do not mind kudos...I do enjoy giving some for help

Re: What is the area of circle passing points A, B & C (in the   [#permalink] 17 Sep 2013, 07:21
    Similar topics Author Replies Last post
Similar
Topics:
3 Experts publish their posts in the topic If points A, B, and C lie on a circle of radius 1, what is zaur2010 14 19 Mar 2011, 12:20
6 Experts publish their posts in the topic Circle C is in the xy-plane, what is the area of the circle? jitendra 6 25 Aug 2010, 03:46
9 Experts publish their posts in the topic Points A, B, and C lie on a circle of radius 1. What is the Economist 18 27 Sep 2009, 08:00
Experts publish their posts in the topic Points A, B, and C lie on a circle of radius. What is the bmwhype2 5 19 Nov 2007, 05:42
Pints A,B,C lie on a circle with radius 1. What is the area anonymousegmat 6 24 Jul 2007, 12:01
Display posts from previous: Sort by

What is the area of circle passing points A, B & C (in the

  Question banks Downloads My Bookmarks Reviews Important topics  


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®.