Live GMAT classes with Target Test Prep start Nov 21 and Nov 22. First class free.

See classes
Target Test Prep · GMAT

Choose how you want to prepare

Learn live with an expert or move at your own pace. Every option includes the complete TTP study system.

Newsweek Readers’ Choice Awards 2026 winner: Target Test Prep, #1 Test Prep

Target Test Prep was voted #1 Best Test Prep in the 2026 Newsweek Readers’ Choice™ Awards.

★★★★★5.0563 reviews
GMATLiveTeachStarts Nov 22
Josh Braslow, Target Test Prep GMAT expert
LIVE ONLINE CLASSES

Get Ready for GMAT Test Day Faster with Live Online Classes

with Josh Braslow, 20+ years in test prep

Nov 22 · Josh Braslow
Sun · 9:30 AM to 12:30 PM ET
Included
40 hours of live online classes + 6 months of TTP OnDemand
  • Attend the first class for free
  • Every class is recorded, so you never fall behind
View classes & enroll
Limited seats availableTarget Test Prep
EALiveTeachOnDemandStart anytime
EXECUTIVE ASSESSMENT

Target Test Prep EA OnDemand

Self-paced EA prep. Study on your schedule.

EXECUTIVE ASSESSMENT

with

165+ EA score guarantee
$05-day trial no automatic billing
Schedule
Included
40 hours of live online classes plus six months of access to the complete TTP EA OnDemand course.
  • 165+ EA Score Guarantee
  • 4,100+ Quant, Verbal, and Integrated Reasoning practice questions
  • 400+ hours of in-depth video lessons
  • 3,000+ step-by-step video solutions
View EA class & enroll Start free 5-day trial
Limited cohort · enrollment openTrial includes full course accessTarget Test Prep
GMATOnDemandStart anytime
SELF-PACED MASTERCLASS

Target Test Prep GMAT OnDemand

Complete access from day one. Study on your schedule.

715+ score guarantee
$0to start then $127/mo
  • Personalized study plan and analytics
  • Thousands of lessons and practice questions
Start free 5-day trial
Read 563 reviewsTarget Test Prep

Circle Geometry

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16206
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770
by Brent@GMATPrepNow » Sat Dec 13, 2008 11:29 am
Image
Last edited by Brent@GMATPrepNow on Sat Dec 13, 2008 11:37 am, edited 1 time in total.
Top
Join the discussion
Source: — Problem Solving |
Senior | Next Rank: 100 Posts
Posts: 59
Joined: Fri Feb 29, 2008 9:00 am
Thanked: 4 times

by agoyal2 » Sat Dec 13, 2008 11:55 am
IMO B.

Take the centre of the circle as O.
The Angle AOB will be 2x. And since AB = AO = BO, AOB is an equilateral traingle, hence 2x = 60 and x=30.
Top
Join the discussion

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16206
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Sat Dec 13, 2008 5:31 pm
Yes, the OA is B

Here's my solution:

Image
Top
Join the discussion
User avatar
Junior | Next Rank: 30 Posts
Posts: 23
Joined: Thu Nov 06, 2008 9:46 pm
Thanked: 1 times

by Tomn » Tue Dec 16, 2008 7:56 pm
Ah yes, you have to remember the equilateral triangle rule...
Top
Join the discussion
User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pmFollowed by: 25 members
Thanked: 237 times
GMAT Score:730

by logitech » Tue Dec 16, 2008 9:28 pm
Who knows how to use that 50 degree to solve this problem ? B-)
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 61
Joined: Mon Nov 17, 2008 11:35 pmFollowed by: 1 member
Thanked: 6 times

by brb588 » Tue Dec 16, 2008 10:09 pm
Brent Hanneson wrote:Yes, the OA is B

Here's my solution:

Image
Okay, I totally cannot figure this problem out. I realized quickly that there was an equilateral triangle in the circle. However, I have no idea how you reached your fourth statement. Do you mind clarifying it for me?
Top
Join the discussion

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16206
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Tue Dec 16, 2008 11:12 pm
There's a rule in circle geometry stating that if a central angle (from the center) and an inscribed angle (from a point on the circle) both hold/contain the same chord then the central angle is twice the inscribed angle.

Image

So, if the central angle is 60, then the inscribed angle must be 30

I hope that helps
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Senior | Next Rank: 100 Posts
Posts: 61
Joined: Mon Nov 17, 2008 11:35 pmFollowed by: 1 member
Thanked: 6 times

by brb588 » Wed Dec 17, 2008 9:56 am
Ah, I could eye that it was 30, but I didn't trust it. Thanks as always.
Top
Join the discussion
Newbie | Next Rank: 10 Posts
Posts: 2
Joined: Sun Dec 21, 2008 5:20 pm

Squares inscribed in a Semi Circle - Circle Geometry

by rg2345 » Mon Dec 29, 2008 7:14 am
In the attached question, can we assume that the side of the smaller square is half the side of the larger one? If yes, how?
You do not have the required permissions to view the files attached to this post.
Top
Join the discussion
User avatar
Legendary Member
Posts: 985
Joined: Wed Dec 20, 2006 11:07 amFollowed by: 1 member
Location: India
Thanked: 51 times

by gabriel » Fri Jan 02, 2009 8:14 pm
Thread moved to the problem solving section.

Brent thanks for sharing the questions with our community.
Top
Join the discussion
User avatar
Legendary Member
Posts: 546
Joined: Sun Nov 16, 2008 11:00 pm
Location: New Delhi , India
Thanked: 13 times

by ronniecoleman » Sun Jan 04, 2009 10:26 pm
IMO B
use theorm:

1. arc subtend double the angle at centre than at any other point..
2. All angles of equilateral triangle are equal
Admission champion, Hauz khaz
011-27565856
Top
Join the discussion