It is currently 24 Nov 2017, 06:46

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

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

Events & Promotions

Events & Promotions in June
Open Detailed Calendar

Find the attachment. I tried adding the image in the post;

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics
Author Message
Manager
Joined: 11 Apr 2011
Posts: 104

Kudos [?]: 32 [0], given: 16

Find the attachment. I tried adding the image in the post; [#permalink]

Show Tags

16 May 2011, 12:25
00:00

Difficulty:

(N/A)

Question Stats:

29% (01:14) correct 71% (01:48) wrong based on 8 sessions

HideShow timer Statistics

Find the attachment. I tried adding the image in the post; however, all in vain. So, attached the complete question.

Attachment:

1.jpg [ 25.68 KiB | Viewed 1201 times ]

Attachments

question.doc [54 KiB]

Last edited by gurpreetsingh on 16 May 2011, 12:56, edited 1 time in total.
Question added from the document

Kudos [?]: 32 [0], given: 16

CEO
Status: Nothing comes easy: neither do I want.
Joined: 12 Oct 2009
Posts: 2756

Kudos [?]: 1912 [1], given: 235

Location: Malaysia
Concentration: Technology, Entrepreneurship
Schools: ISB '15 (M)
GMAT 1: 670 Q49 V31
GMAT 2: 710 Q50 V35
Re: co-ordinate geometry question [#permalink]

Show Tags

16 May 2011, 13:01
1
KUDOS
Statement 1 : Not sufficient.
We know the position of B, but not the position of A. Thus we can not calculate the value of AB.

Statement 2: Sufficient.
We know the position of C
=> we know the perpendicular distance from the line AB
=> we know the altitude of the triangle
=> we have the area.

Hence the Answer is B.
_________________

Fight for your dreams :For all those who fear from Verbal- lets give it a fight

Money Saved is the Money Earned

Jo Bole So Nihaal , Sat Shri Akaal

Support GMAT Club by putting a GMAT Club badge on your blog/Facebook

GMAT Club Premium Membership - big benefits and savings

Gmat test review :
http://gmatclub.com/forum/670-to-710-a-long-journey-without-destination-still-happy-141642.html

Kudos [?]: 1912 [1], given: 235

Math Forum Moderator
Joined: 20 Dec 2010
Posts: 1964

Kudos [?]: 2102 [0], given: 376

Re: co-ordinate geometry question [#permalink]

Show Tags

16 May 2011, 13:04
Attachment:

Area_Of_Equilateral_triangle.PNG [ 15.53 KiB | Viewed 1192 times ]

(1)
A can be (0, 0.000000000001)
Or
A can be (0, 5)
Both resulting in different area for ABC.
Not Sufficient.

(2)
We know the altitude of the triangle.
Distance between y-axis and coordinate C or 6.
Thus, the area can be found.

$$Altitude=\frac{\sqrt{3}}{2}*(Side)=6$$

$$Area = \frac{\sqrt{3}}{4}(side)^2$$

Sufficient.

Ans: "B"
_________________

Kudos [?]: 2102 [0], given: 376

Senior Manager
Joined: 03 Mar 2010
Posts: 421

Kudos [?]: 368 [0], given: 22

Schools: Simon '16 (M)
Re: co-ordinate geometry question [#permalink]

Show Tags

16 May 2011, 13:29
Stmt1 . We know only one co-ordinate. we don't know altitude, base or one side of triangle. Hence insufficient.

Stmt2: We know altitude when draw from C to opposite base is 6. Also this altitude will bisect the angle ACB making each angle 30.
So cos30 = altitude/CA {imagine a line from C to AB}
$$\sqrt{3}/2=6/CA$$

$$CA= 12/\sqrt{3}.$$ We know one side of EQUILATERAL triangle.

$$Apply formula Area of equilateral triangle= s^2 * \sqrt{3}/4 = (12/\sqrt{3})^2* \sqrt{3}/4 = 12\sqrt{3}$$
Hence sufficient.

OA B.
_________________

My dad once said to me: Son, nothing succeeds like success.

Last edited by jamifahad on 16 May 2011, 13:53, edited 1 time in total.

Kudos [?]: 368 [0], given: 22

Math Forum Moderator
Joined: 20 Dec 2010
Posts: 1964

Kudos [?]: 2102 [0], given: 376

Re: co-ordinate geometry question [#permalink]

Show Tags

16 May 2011, 13:40
So sin30 = altitude/CA {imagine a line from C to AB}

I know it doesn't change the answer. But, is it sin{30} or cos{30}?
_________________

Kudos [?]: 2102 [0], given: 376

Senior Manager
Joined: 03 Mar 2010
Posts: 421

Kudos [?]: 368 [0], given: 22

Schools: Simon '16 (M)
Re: co-ordinate geometry question [#permalink]

Show Tags

16 May 2011, 13:55
oh yes cos30. i was timing my solution. got mixed up. thanks.
_________________

My dad once said to me: Son, nothing succeeds like success.

Kudos [?]: 368 [0], given: 22

VP
Status: There is always something new !!
Affiliations: PMI,QAI Global,eXampleCG
Joined: 08 May 2009
Posts: 1283

Kudos [?]: 286 [0], given: 10

Re: co-ordinate geometry question [#permalink]

Show Tags

16 May 2011, 20:11
a the distance from origin to A is not known.Hence side of the equilateral triangle cannot be calculated. Not sufficient.

b C has x coordinate = 6 = altitude of equilateral triangle
y coordinate = 3* 3^(1/2) also does not account for the distance from origin to A.

however altitude a = 6 means side = 6*2/3^(1/2) as in a triangle with angle 60 deg sides are in the ratio 3^(1/2)(perpendicular):1 (base):2(hypotenuse)

thus area can be calculated.

B
_________________

Visit -- http://www.sustainable-sphere.com/
Promote Green Business,Sustainable Living and Green Earth !!

Kudos [?]: 286 [0], given: 10

Manager
Joined: 11 Apr 2011
Posts: 104

Kudos [?]: 32 [0], given: 16

Re: co-ordinate geometry question [#permalink]

Show Tags

17 May 2011, 07:19
Thanks guys, indeed the OA is B.

Kudos [?]: 32 [0], given: 16

Manager
Status: GMAT in 4 weeks
Joined: 28 Mar 2010
Posts: 179

Kudos [?]: 193 [0], given: 25

GPA: 3.89
Re: co-ordinate geometry question [#permalink]

Show Tags

17 May 2011, 10:39
Yup B is sufficient

With point C there is only one possible equilateral triangle. Hence we can find it area
_________________

If you liked my post, please consider a Kudos for me. Thanks!

Kudos [?]: 193 [0], given: 25

TOEFL Forum Moderator
Joined: 16 Nov 2010
Posts: 1602

Kudos [?]: 601 [0], given: 40

Location: United States (IN)
Concentration: Strategy, Technology
Re: co-ordinate geometry question [#permalink]

Show Tags

18 May 2011, 04:48
(1)
Let Co-ord of A = (0,y)

5root(3) - y = Side

Insufficient

(2)

A median drawn from C will bisect AB

and there will be 30-60-90 triangle

The length of perpendicular is known

so other sides can be found, and this the area can be found

Sufficient

_________________

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

GMAT Club Premium Membership - big benefits and savings

Kudos [?]: 601 [0], given: 40

Re: co-ordinate geometry question   [#permalink] 18 May 2011, 04:48
Display posts from previous: Sort by

Find the attachment. I tried adding the image in the post;

 new topic post reply Question banks Downloads My Bookmarks Reviews Important topics

 Powered by phpBB © phpBB Group | Emoji artwork provided by EmojiOne 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®.