GMAT Question of the Day - Daily to your Mailbox; hard ones only

It is currently 23 May 2019, 12:49

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.

Close

Request Expert Reply

Confirm Cancel

In the circle above with center O, what is the measure of angle AOB?

  new topic post reply Question banks Downloads My Bookmarks Reviews Important topics  
Author Message
TAGS:

Hide Tags

 
Math Expert
User avatar
V
Joined: 02 Sep 2009
Posts: 55265
In the circle above with center O, what is the measure of angle AOB?  [#permalink]

Show Tags

New post 13 Sep 2018, 02:34
00:00
A
B
C
D
E

Difficulty:

  45% (medium)

Question Stats:

71% (01:32) correct 29% (01:23) wrong based on 42 sessions

HideShow timer Statistics

CEO
CEO
User avatar
D
Status: GMATINSIGHT Tutor
Joined: 08 Jul 2010
Posts: 2931
Location: India
GMAT: INSIGHT
Schools: Darden '21
WE: Education (Education)
Reviews Badge
In the circle above with center O, what is the measure of angle AOB?  [#permalink]

Show Tags

New post Updated on: 15 Sep 2018, 00:35
1
Bunuel wrote:
Image
In the circle above with center O, what is the measure of angle AOB?

(1) The length of the arc AB is π.
(2) The measure of angle ABO is equal to the measure of angle OBC.


Attachment:
image011.gif


Question: what is the measure of angle AOB?

Statement 1: The length of the arc AB is π.

i.e. (Angle AOB/360)*2*π*r = π
But neither do we have angle nor the radius hence nothing can be concluded about the angle ABO hence
NOT SUFFICIENT

Statement 2: he measure of angle ABO is equal to the measure of angle OBC.
While Sum of Angles ABO and OBC = 90º (Property: Any angle on circumference in a semicircle is 90º )
If both angles are equal then each angle must be = 45º
i.e. ABC is an isosceles right angle triangle and OB is perpendicular on AC
i.e. angle AOB = 90º

SUFFICIENT

Answer: option B
_________________
Prosper!!!
GMATinsight
Bhoopendra Singh and Dr.Sushma Jha
e-mail: info@GMATinsight.com I Call us : +91-9999687183 / 9891333772
Online One-on-One Skype based classes and Classroom Coaching in South and West Delhi
http://www.GMATinsight.com/testimonials.html

ACCESS FREE GMAT TESTS HERE:22 ONLINE FREE (FULL LENGTH) GMAT CAT (PRACTICE TESTS) LINK COLLECTION

Originally posted by GMATinsight on 13 Sep 2018, 03:05.
Last edited by GMATinsight on 15 Sep 2018, 00:35, edited 2 times in total.
Manager
Manager
User avatar
G
Joined: 21 Jun 2017
Posts: 234
Concentration: Finance, Economics
WE: Corporate Finance (Commercial Banking)
Re: In the circle above with center O, what is the measure of angle AOB?  [#permalink]

Show Tags

New post 14 Sep 2018, 10:10
1. Is AOB not a straight line. I think it is the diameter even if it has not been explicitly stated. Consequently, ABC is 90. Am i wrong ?

2. In your explanation how come ABO and OBC sum to be 180 ??

3. Cant we assume that since angle ABC is 90 , the radius OB must bisect ABC. If not, why so. Both the traigles are similar


Please guide
_________________
Even if it takes me 30 attempts, I am determined enough to score 740+ in my 31st attempt. This is it, this is what I have been waiting for, now is the time to get up and fight, for my life is 100% my responsibility.

Dil ye Ziddi hai !!!
Intern
Intern
avatar
B
Joined: 15 Jul 2018
Posts: 3
Re: In the circle above with center O, what is the measure of angle AOB?  [#permalink]

Show Tags

New post 14 Sep 2018, 10:28
Hey GMATInsight


Here sum of angle ABO & OBC would be 90 and not 180
Manager
Manager
avatar
S
Joined: 19 Apr 2017
Posts: 78
Concentration: General Management, Sustainability
Schools: ESSEC '22
GPA: 3.9
WE: Operations (Hospitality and Tourism)
In the circle above with center O, what is the measure of angle AOB?  [#permalink]

Show Tags

New post 14 Sep 2018, 13:36
(1) The length of the arc AB is = \(Arc Length=π =(Angle of the arc/360°)*Circumference\)-> radius is unknown

(2) The measure of angle ABO is equal to the measure of angle OBC.
In triangle ABO and OBC we have
a) OB is part of both the triangle = common side
b) AO=OC= radius= common side
c) From Statement 2 angle ABO =Angle OBC = angle congruent
SAS triangles are congruent

AC = diameter... If a triangle is inscribed in a circle and has the diameter of the circle as the triangle’s hypotenuse, then that triangle is a right triangle.

so 2*angle ABO=90 ->angle ABO = 45
Angle BAO = Angle ABO = 45
Angle AOB = 90
So B


do correct me if i am wrong. thanks in advance :)
GMAT Club Bot
In the circle above with center O, what is the measure of angle AOB?   [#permalink] 14 Sep 2018, 13:36
Display posts from previous: Sort by

In the circle above with center O, what is the measure of angle AOB?

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


Copyright

GMAT Club MBA Forum Home| About| Terms and Conditions and Privacy Policy| GMAT Club Rules| Contact| Sitemap

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®.