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

 It is currently 02 Jul 2015, 22:37

### 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

# What is the perimeter of quadrangle ABCD in which a circle

Author Message
TAGS:
Senior Manager
Joined: 15 Aug 2007
Posts: 252
Schools: Chicago Booth
Followers: 1

Kudos [?]: 56 [0], given: 0

What is the perimeter of quadrangle ABCD in which a circle [#permalink]  21 Mar 2008, 21:16
3
This post was
BOOKMARKED
00:00

Difficulty:

(N/A)

Question Stats:

0% (00:00) correct 0% (00:00) wrong based on 1 sessions
What is the perimeter of quadrangle ABCD in which a circle is inscribed?

1) AB+DC=8
2) BC=5
Attachments

untitled.JPG [ 5.22 KiB | Viewed 2122 times ]

CEO
Joined: 17 Nov 2007
Posts: 3574
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 414

Kudos [?]: 2243 [3] , given: 359

3
KUDOS
Expert's post
A

1) AB+DC=8
LB=BM, MC=CN, ND=DP, PA=AL
P=AB+BC+DC+DA=(AB+DC)+(BC+DA)=8+(BM+MC+DP+DA)=8+(BL+NC+DN+AL)=8+(AB+DC)=16
Sufficient

2) insufficient

By the way, we have a typical pattern of GMAT DS trap (A,B vs C):
the fist condition is complex and seems to be insufficient
the second condition is very simple and insufficient. It would help to support fist condition.
Attachments

t61627.png [ 9 KiB | Viewed 2056 times ]

_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Senior Manager
Joined: 15 Aug 2007
Posts: 252
Schools: Chicago Booth
Followers: 1

Kudos [?]: 56 [0], given: 0

walker wrote:
A

1) AB+DC=8
LB=BM, MC=CN, ND=DP, PA=AL
P=AB+BC+DC+DA=(AB+DC)+(BC+DA)=8+(BM+MC+DP+DA)=8+(BL+NC+DN+AL)=8+(AB+DC)=16
Sufficient

2) insufficient

By the way, we have a typical pattern of GMAT DS trap (A,B vs C):
the fist condition is complex and seems to be insufficient
the second condition is very simple and insufficient. It would help to support fist condition.

Thanks walker. excellent explanation!
Current Student
Joined: 28 Dec 2004
Posts: 3387
Location: New York City
Schools: Wharton'11 HBS'12
Followers: 14

Kudos [?]: 186 [0], given: 2

Nice explanation..i get why its A..
Manager
Joined: 25 Mar 2008
Posts: 106
Followers: 1

Kudos [?]: 12 [0], given: 0

pls explain why

LB=BM, MC=CN, ND=DP, PA=AL

what is the formula for this ?
CEO
Joined: 17 Nov 2007
Posts: 3574
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 414

Kudos [?]: 2243 [0], given: 359

Expert's post
shobuj wrote:
pls explain why

LB=BM, MC=CN, ND=DP, PA=AL

what is the formula for this ?

Let O is the center of the circle.

OL=OM - the radius of the circle
OLB=90, OMB=90 - properties of a tangent line

OB is common for triangles OLB and OMB

So, triangles OLB and OMB are equal, and LB=BM.
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Manager
Joined: 25 Mar 2008
Posts: 106
Followers: 1

Kudos [?]: 12 [0], given: 0

thanks walker nice explaination

u make me greatful to u by ur several explaination

but here is

i wanna know

though OB is common and OL=OM why LB=LM is this another properties

if both <OLB=<OMB AND OL=OM therefore LB=LM
Director
Joined: 20 Feb 2008
Posts: 797
Location: Texas
Schools: Kellogg Class of 2011
Followers: 6

Kudos [?]: 145 [0], given: 9

shobuj wrote:
thanks walker nice explaination

u make me greatful to u by ur several explaination

but here is

i wanna know

though OB is common and OL=OM why LB=LM is this another properties

if both <OLB=<OMB AND OL=OM therefore LB=LM

I think you mean LB=BM, BO is the common side with B being the middle point.
CEO
Joined: 17 Nov 2007
Posts: 3574
Concentration: Entrepreneurship, Other
Schools: Chicago (Booth) - Class of 2011
GMAT 1: 750 Q50 V40
Followers: 414

Kudos [?]: 2243 [0], given: 359

Expert's post
shobuj wrote:
though OB is common and OL=OM why LB=LM is this another properties

if both <OLB=<OMB AND OL=OM therefore LB=LM

We have here two right triangles with the same hypotenuse and the same leg. So, we can express LB and MB as sqrt(OB^2-OL^2) and sqrt(OB^2-OM^2). As OL=OM --> LB=MB
_________________

HOT! GMAT TOOLKIT 2 (iOS) / GMAT TOOLKIT (Android) - The OFFICIAL GMAT CLUB PREP APP, a must-have app especially if you aim at 700+ | PrepGame

Director
Joined: 05 Jan 2008
Posts: 707
Followers: 3

Kudos [?]: 158 [0], given: 0

very nice explanation Walker!
_________________

Persistence+Patience+Persistence+Patience=G...O...A...L

Similar topics Replies Last post
Similar
Topics:
2 If the perimeter of quadrilateral ABCD is 4, what is its area? 2 09 Dec 2014, 05:58
1 What is the perimeter of rectangle ABCD ? 8 29 Sep 2011, 05:05
Which of two quadrangles ABCD, or EFGH has the largest area? 2 17 Dec 2006, 22:26
There is a quadrangle ABCD(Clock-wise). Is ABCD a square? 1) 7 18 Jan 2006, 04:21
What is the perimeter of rhombus ABCD? (1) Area of ABCD is 6 15 Sep 2005, 15:54
Display posts from previous: Sort by