BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem
TTP OnDemand GMAT Video Course
Featured Course

Target Test Prep GMAT OnDemand

Scott Woodbury-Stewart’s private virtual classroom — 400 hours of master-class video lessons for the GMAT Focus Edition.

  • 715+ score guarantee — highest in the industry (99th percentile)
  • 52 chapters · 1,500+ lessons · 4,000+ practice questions
  • 400 hours of video · 1,500+ instructor-led HD smartboard lessons
  • 300,000+ students accepted to Harvard, Stanford, Wharton, Booth & Sloan & more
  • 24/7 live support + weekly Zoom office hours with GMAT instructors
  • TTP AI Assist — 24/7 AI-powered virtual tutor for instant help
  • 1,200+ flashcards + AI-powered study assistant & daily calendar
  • OnDemand, LiveTeach & GMAT Bootcamp formats available
  • Also: GRE, SAT Math & Executive Assessment courses
  • MBA Admissions Consulting now available
  • 🏆 2025 EdTech Breakthrough Award: Test Prep Solution Provider of the Year
  • 200,000+ students served
  • 5-day free trial — $0 to start, no auto-billing, cancel anytime
★★★★★ 5.0 (559 reviews)
130-pt guarantee
$0 to start then $127/mo
Start Free 5-Day Trial Read 559 Reviews →

Circle Geometry

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
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
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
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
Log in to postLogin with Googleuse password
QUOTE IN REPLY
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
Log in to postLogin with Googleuse password
QUOTE IN REPLY
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
Log in to postLogin with Googleuse password
QUOTE IN REPLY
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
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
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
Log in to postLogin with Googleuse password
QUOTE IN REPLY
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
Log in to postLogin with Googleuse password
QUOTE IN REPLY
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?
Attachments
squares inscribed a semi circle.pdf
Squares inscribed in a Semi Circle
(145.26 KiB) Downloaded 126 times
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
User avatar
Legendary Member
Posts: 986
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
Log in to postLogin with Googleuse password
QUOTE IN REPLY
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
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1