Author 
Message 
Manager
Joined: 24 Jun 2006
Posts: 127

In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
16 Jul 2007, 13:44
Question Stats:
42% (00:59) correct 58% (00:35) wrong based on 41 sessions
HideShow timer Statistics
In triangle ABC above, what is the lenght of side BC? 1) line segment AD has lenght 6 2) x=36 OPEN DISCUSSION OF THIS QUESTION IS HERE: https://gmatclub.com/forum/intriangle ... 68281.html
Official Answer and Stats are available only to registered users. Register/ Login.
Attachments
atriangle.JPG [ 3.03 KiB  Viewed 2811 times ]



Senior Manager
Joined: 06 Mar 2006
Posts: 482

Re: In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
16 Jul 2007, 14:03
Where is the figure? Without the figure, it is kind of hard to picture where x is and where point D lies.



Manager
Joined: 24 Jun 2006
Posts: 127

Re: In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
16 Jul 2007, 14:06
don't you see it?? i ve attached it with the post... ????



Senior Manager
Joined: 06 Mar 2006
Posts: 482

Re: In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
16 Jul 2007, 14:57
1
This post received KUDOS
Sorry, I did see it now.
The answer should be A.
We know from the figure that <BAC=x , <BDC=<BCD=2x
So BD=BC, since <BDC=<BAC+<ABD, this tells you <ABD=x as well.
Therefore, AD=BD, since we have already find out that BD=BC, so AD=BC. Statement 1 alone is sufficient.
Statement 2 tells you the value of X, but didn't tell you anything about the length of the segment, therefore is not sufficient.



Intern
Joined: 19 Oct 2010
Posts: 1

Re: In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
23 Oct 2010, 15:12
Awesome Just one simple explanation for how <BDC = <BAC+<ABD, exterior angle in a triangle is the sum of the opposite interior angles. It took me a while to figure it out, may be helpful.



Retired Moderator
Status: 2000 posts! I don't know whether I should feel great or sad about it! LOL
Joined: 04 Oct 2009
Posts: 1476
Location: Peru
Schools: Harvard, Stanford, Wharton, MIT & HKS (Government)
WE 1: Economic research
WE 2: Banking
WE 3: Government: Foreign Trade and SMEs

Re: In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
08 Nov 2010, 06:06
+1 A
_________________
"Life’s battle doesn’t always go to stronger or faster men; but sooner or later the man who wins is the one who thinks he can."
My Integrated Reasoning Logbook / Diary: http://gmatclub.com/forum/myirlogbookdiary133264.html
GMAT Club Premium Membership  big benefits and savings



Manager
Status: Planning to retake.
Affiliations: Alpha Psi Omega
Joined: 25 Oct 2010
Posts: 86
Concentration: General Management, Entrepreneurship
GRE 1: 1310 Q630 V680
GPA: 3.16

Re: In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
22 Nov 2010, 09:17
I was going to pick A originally, but upon seeing that x=36 (I assumed that x should be 30), I felt no choice but to pick C. Why is it unnecessary to know what x is?
_________________
Did I help you? Please give me kudos.
Each moment of time ought to be put to proper use, either in business, in improving the mind, in the innocent and necessary relaxations and entertainments of life, or in the care of the moral and religious part of our nature.
William Andrus Alcott



Intern
Joined: 18 Aug 2009
Posts: 36
Location: United States
Concentration: Finance, Entrepreneurship
GPA: 3.29
WE: Engineering (Consulting)

Re: In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
22 Nov 2010, 13:15
rockzom wrote: I was going to pick A originally, but upon seeing that x=36 (I assumed that x should be 30), I felt no choice but to pick C.
Why is it unnecessary to know what x is? Regardless of the actual value of x, we can show that triangle ADB is an isosceles triangle. Within the bounds of the givens in this problem, changing x will only lead to changes in the length of side AB and DC.



Manager
Joined: 01 Nov 2010
Posts: 165
Location: Zürich, Switzerland

Re: In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
22 Nov 2010, 13:36
(180 2x) + x + ABD = 180
therefore x= abd
So, AB=BD=BC=6; Answer A is sufficient.
B is not sufficient since merely knowing angles does not reach upon length of AB.
Answer: A



Math Expert
Joined: 02 Sep 2009
Posts: 44336

Re: In triangle ABC above, what is the lenght of side BC? 1) [#permalink]
Show Tags
21 Aug 2017, 07:01




Re: In triangle ABC above, what is the lenght of side BC? 1)
[#permalink]
21 Aug 2017, 07:01






