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

 It is currently 06 May 2015, 17:03

### 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

# Equilateral triangle ABC is inscribed inside a circle. Arc

Author Message
TAGS:
Director
Joined: 11 Sep 2006
Posts: 514
Followers: 2

Kudos [?]: 35 [0], given: 0

Equilateral triangle ABC is inscribed inside a circle. Arc [#permalink]  14 Oct 2006, 11:48
Equilateral triangle ABC is inscribed inside a circle. Arc ABC measures 24; what is the diameter of the circle?

Answer was 11. Would someone kindly explain? Thanks.
_________________

...there ain't no such thing as a free lunch...

Manager
Joined: 01 Oct 2006
Posts: 242
Followers: 1

Kudos [?]: 5 [0], given: 0

Re: geometry question on Powerprep [#permalink]  14 Oct 2006, 12:04
Without any diagram given, this is how I started solving it.

An equilateral triangle inscribed in a circle will create 3 arcs: AB, BC and CA.

Let the center of circle be O. Then angle AOC = angle AOB = angle BOC = 120 degrees (2 x 60)

Thus arc AB=arc BC=arc AC
Therefore ARC ABC = 2/3 x perimeter of circle

24 = 2/3 x Pi x D
D= 36/Pi

But this gives me the diameter as 11.45 and not 11. So, I am not sure where am I going wrong,
Director
Joined: 11 Sep 2006
Posts: 514
Followers: 2

Kudos [?]: 35 [0], given: 0

Actually, the problem called for the "approximate" value of the diameter. So you are right. Thanks.
_________________

...there ain't no such thing as a free lunch...

Similar topics Replies Last post
Similar
Topics:
An equilateral triangle ABC is inscribed in the circle. If 2 23 Apr 2011, 14:32
Equilateral Triangle ABC is inscribed in a circle. The arc 9 20 May 2007, 14:30
An equilateral triangle ABC is inscribed inside a circle 3 01 Feb 2007, 04:14
Equilateral triangle ABC is inscribed in the circle. If the 1 12 Nov 2006, 04:10
A circle is inscribed in equilateral triangle ABC such that 6 01 Oct 2006, 10:43
Display posts from previous: Sort by