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

It is currently 25 Jul 2014, 01:12

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

Geometry II = #12

  Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
Senior Manager
Senior Manager
User avatar
Joined: 10 Dec 2008
Posts: 483
Location: United States
GMAT 1: 760 Q49 V44
GPA: 3.9
Followers: 28

Kudos [?]: 107 [0], given: 12

GMAT Tests User
Geometry II = #12 [#permalink] New post 05 Aug 2009, 17:41
Apologize that I can't determine whether this thread already exists...

In quadrilateral ABCD , AB = CD and BC = AD . If \angle CBD = 30 degrees and \angle BAD = 80 degrees, what is the value of \angle ADC ?

(C) 2008 GMAT Club - Geometry - II#12

* 30 degrees
* 50 degrees
* 70 degrees
* 100 degrees
* 120 degrees

Given the question, doesn't that violate the rules of a parallelogram? I just can't seem to draw this figure out as a parallelogram. somebody help please? :roll:
Kaplan Promo CodeKnewton GMAT Discount CodesVeritas Prep GMAT Discount Codes
4 KUDOS received
Intern
Intern
avatar
Joined: 06 Aug 2009
Posts: 2
Followers: 0

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

Re: Geometry II = #12 [#permalink] New post 06 Aug 2009, 10:55
4
This post received
KUDOS
bipolarbear wrote:
I thought that a parallelogram had to have 2 adjacent angles add up to 180. Can someone attach a drawing of this figure please?

OA is D.


Hey! I got D as an answer as well and I think I can explain it. I attached a drawing I created in Paint so hopefully that'll help too.

Here's how I broke it down:
-They gave two angles, the 30 (CBD) and 80 (BAD).
-I drew in the CBD angle to make it easier to visualize.
-In a parallelogram, when one line (BD) connects the two parallel lines (AD and BC), it creates congruent alternate interior angles (the 30s and the X's). Angles diagonal from eachother also congruent, which is how I got the other 80 (BCD). You can also see that CBA and ADC (the one in question) are also congruent since both of them equal X+30. So we just need to figure out what X is so we can add it to 30 to get the whole angle.
-All the angles inside a parallelogram are supposed to have a sum of 360. So if you take 360 and subtract all the known values (80, 80, 30, 30) you should get a difference of 140.
-Therefore the two remaing angles (the X's) should equal 140. If you set it up as 2x=140 and then divide it out, you'll see that X=70.
-Then X+30 becomes 70+30 which equals 100.

I hope my explanation helps.... and is right :-D Yay for 1st post!
Attachment:
GeoII-12.JPG
GeoII-12.JPG [ 11.59 KiB | Viewed 1236 times ]
Expert Post
1 KUDOS received
Math Expert
User avatar
Joined: 02 Sep 2009
Posts: 18733
Followers: 3243

Kudos [?]: 22380 [1] , given: 2616

Re: Geometry II = #12 [#permalink] New post 19 Feb 2013, 04:23
1
This post received
KUDOS
Expert's post
Sachin9 wrote:
Bunuel,
In a parallelogram, do we have sum of all interior angles = 360?

do we have any other propery apart from opposite sides and opposite angles being equal?


The sum of interior angles of a polygon is 180(n-2) where n is the number of sides (so is the number of angles). So, the sum of the interior angles of any quadrilateral, including parallelogram, is 180*2=360.

Parallelogram A quadrilateral with two pairs of parallel sides.
Image
Properties and Tips
• Opposite sides of a parallelogram are equal in length.
• Opposite angles of a parallelogram are equal in measure.

• Opposite sides of a parallelogram will never intersect.
• The diagonals of a parallelogram bisect each other.
• Consecutive angles are supplementary, add to 180°.
The area, A, of a parallelogram is A = bh, where b is the base of the parallelogram and h is its height.
• The area of a parallelogram is twice the area of a triangle created by one of its diagonals.

A parallelogram is a quadrilateral with opposite sides parallel and congruent. It is the "parent" of some other quadrilaterals, which are obtained by adding restrictions of various kinds:
• A rectangle is a parallelogram but with all angles fixed at 90°
• A rhombus is a parallelogram but with all sides equal in length
• A square is a parallelogram but with all sides equal in length and all angles fixed at 90°


For other properties check polygons chapter of Math Book: math-polygons-87336.html
_________________

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

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Intern
Intern
avatar
Joined: 09 Feb 2009
Posts: 17
Followers: 0

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

Re: Geometry II = #12 [#permalink] New post 05 Aug 2009, 19:32
bipolarbear wrote:
Apologize that I can't determine whether this thread already exists...

In quadrilateral ABCD , AB = CD and BC = AD . If \angle CBD = 30 degrees and \angle BAD = 80 degrees, what is the value of \angle ADC ?

(C) 2008 GMAT Club - Geometry - II#12

* 30 degrees
* 50 degrees
* 70 degrees
* 100 degrees
* 120 degrees

Given the question, doesn't that violate the rules of a parallelogram? I just can't seem to draw this figure out as a parallelogram. somebody help please? :roll:


not sure how this one works too...
.
but i wanted to know if you were to get any of these questions of a quadrilateral ABCD = how would u determine which points are A, B, C, D? Is it supposed to decided in a clockwise fashion?
CEO
CEO
User avatar
Joined: 29 Aug 2007
Posts: 2501
Followers: 51

Kudos [?]: 484 [0], given: 19

GMAT Tests User
Re: Geometry II = #12 [#permalink] New post 05 Aug 2009, 21:47
bipolarbear wrote:
Apologize that I can't determine whether this thread already exists...

In quadrilateral ABCD , AB = CD and BC = AD . If \angle CBD = 30 degrees and \angle BAD = 80 degrees, what is the value of \angle ADC ?

(C) 2008 GMAT Club - Geometry - II#12

* 30 degrees
* 50 degrees
* 70 degrees
* 100 degrees
* 120 degrees

Given the question, doesn't that violate the rules of a parallelogram? I just can't seem to draw this figure out as a parallelogram. somebody help please? :roll:


Parallelogram = a quadilateral with opposit equal and parallel sides.
How the rules of a parallelogram are violated?

Did you get D. 100 degrees?
_________________

Verbal: new-to-the-verbal-forum-please-read-this-first-77546.html
Math: new-to-the-math-forum-please-read-this-first-77764.html
Gmat: everything-you-need-to-prepare-for-the-gmat-revised-77983.html


GT

Manager
Manager
avatar
Joined: 14 Jun 2009
Posts: 97
Followers: 2

Kudos [?]: 3 [0], given: 9

Re: Geometry II = #12 [#permalink] New post 05 Aug 2009, 22:05
i got the answer as D>100 degrees, by drawing a figure, and simply using the properties of parallel lines...

wats the OA..
Senior Manager
Senior Manager
User avatar
Joined: 10 Dec 2008
Posts: 483
Location: United States
GMAT 1: 760 Q49 V44
GPA: 3.9
Followers: 28

Kudos [?]: 107 [0], given: 12

GMAT Tests User
Re: Geometry II = #12 [#permalink] New post 06 Aug 2009, 09:37
I thought that a parallelogram had to have 2 adjacent angles add up to 180. Can someone attach a drawing of this figure please?

OA is D.
Expert Post
Founder
Founder
User avatar
Affiliations: UA-1K, SPG-G, HH-D
Joined: 04 Dec 2002
Posts: 12017
Location: United States (WA)
GMAT 1: 750 Q49 V42
GPA: 3.5
WE: Information Technology (Hospitality and Tourism)
Followers: 2161

Kudos [?]: 7603 [0], given: 3626

GMAT ToolKit User Premium Member CAT Tests
Re: Geometry II = #12 [#permalink] New post 06 Aug 2009, 11:23
Expert's post
TheCojones wrote:


al 140. If you set it up as 2x=140 and then divide it out, you'll see that X=70.
-Then X+30 becomes 70+30 which equals 100.

I hope my explanation helps.... and is right :-D Yay for 1st post!


Kudos! and welcome to GMAT Club!
_________________

Founder of GMAT Club

Just starting out with GMAT? Start here... | Want to know your GMAT Score? Try GMAT Score Estimator
Need GMAT Book Recommendations? Best GMAT Books

Co-author of the GMAT Club tests

Have a blog? Feature it on GMAT Club!

Get the best GMAT Prep Resources with GMAT Club Premium Membership

Senior Manager
Senior Manager
User avatar
Joined: 10 Dec 2008
Posts: 483
Location: United States
GMAT 1: 760 Q49 V44
GPA: 3.9
Followers: 28

Kudos [?]: 107 [0], given: 12

GMAT Tests User
Re: Geometry II = #12 [#permalink] New post 06 Aug 2009, 11:43
TheCojones wrote:
Hey! I got D as an answer as well and I think I can explain it. I attached a drawing I created in Paint so hopefully that'll help too.


Wow, thanks! Now it all makes sense 8-) . kudos to you! Hopefully you can stick around here and make use of these awesome forums (ehhh, not just for my sake :-D ) !
Intern
Intern
avatar
Joined: 06 Aug 2009
Posts: 2
Followers: 0

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

Re: Geometry II = #12 [#permalink] New post 06 Aug 2009, 11:59
hehe thanks guys! I just found this site today and have already been stuck on it for a good couple of hours. I'm sure I'll be around :lol:
Director
Director
avatar
Status: Gonna rock this time!!!
Joined: 22 Jul 2012
Posts: 550
Location: India
GMAT 1: 640 Q43 V34
GMAT 2: 630 Q47 V29
WE: Information Technology (Computer Software)
Followers: 2

Kudos [?]: 27 [0], given: 562

GMAT Tests User
Re: Geometry II = #12 [#permalink] New post 19 Feb 2013, 03:28
Bunuel,
In a parallelogram, do we have sum of all interior angles = 360?

do we have any other propery apart from opposite sides and opposite angles being equal?
_________________

hope is a good thing, maybe the best of things. And no good thing ever dies.

Who says you need a 700 ?Check this out : http://gmatclub.com/forum/who-says-you-need-a-149706.html#p1201595

My GMAT Journey : end-of-my-gmat-journey-149328.html#p1197992

Senior Manager
Senior Manager
avatar
Joined: 17 Apr 2013
Posts: 498
Concentration: Entrepreneurship, Leadership
Schools: HBS '16
GMAT Date: 11-30-2013
GPA: 3.3
Followers: 1

Kudos [?]: 36 [0], given: 232

Re: Geometry II = #12 [#permalink] New post 06 Feb 2014, 11:50
Bunuel wrote:
Sachin9 wrote:
Bunuel,
In a parallelogram, do we have sum of all interior angles = 360?

do we have any other propery apart from opposite sides and opposite angles being equal?


The sum of interior angles of a polygon is 180(n-2) where n is the number of sides (so is the number of angles). So, the sum of the interior angles of any quadrilateral, including parallelogram, is 180*2=360.

Parallelogram A quadrilateral with two pairs of parallel sides.
Image
Properties and Tips
• Opposite sides of a parallelogram are equal in length.
• Opposite angles of a parallelogram are equal in measure.

• Opposite sides of a parallelogram will never intersect.
• The diagonals of a parallelogram bisect each other.
• Consecutive angles are supplementary, add to 180°.
The area, A, of a parallelogram is A = bh, where b is the base of the parallelogram and h is its height.
• The area of a parallelogram is twice the area of a triangle created by one of its diagonals.

A parallelogram is a quadrilateral with opposite sides parallel and congruent. It is the "parent" of some other quadrilaterals, which are obtained by adding restrictions of various kinds:
• A rectangle is a parallelogram but with all angles fixed at 90°
• A rhombus is a parallelogram but with all sides equal in length
• A square is a parallelogram but with all sides equal in length and all angles fixed at 90°


For other properties check polygons chapter of Math Book: math-polygons-87336.html


In this questions was it sufficient on the basis of the fact that two opposites sides of a quadliteral are equal so it must be a Parallelogram?
_________________

Like my post Send me a Kudos :) It is a Good manner.

Re: Geometry II = #12   [#permalink] 06 Feb 2014, 11:50
    Similar topics Author Replies Last post
Similar
Topics:
Geometry - II q3 & q9 saruba 5 15 Nov 2009, 10:17
lsat II sec.IV - 12 marcodonzelli 1 26 Feb 2008, 10:31
Geometry -ii alimad 1 23 Nov 2007, 13:12
Which of the following is an integer? I. 12!/6! II. 12!/8! Matrix02 9 27 Nov 2006, 16:47
if t is not equal to 0, is r > 0? i) rt = 12 ii) r + t = jodeci 3 28 Mar 2006, 19:40
Display posts from previous: Sort by

Geometry II = #12

  Question banks Downloads My Bookmarks Reviews Important topics  

Moderators: Bunuel, WoundedTiger



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®.