GRE Prep 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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
In the figure above, the circles centered at O1 and O2 have
[#permalink]
18 May 2020, 17:43
18 May 2020, 17:43
2
Expert Reply
00:00
Question Stats:
66% (01:07) correct
33% (01:52) wrong based on 33 sessions
Hide Show timer Statistics
Attachment:
#greprepclub In the figure above, the circles centered at.jpg [ 14.36 KiB | Viewed 3064 times ]
In the figure above, the circles centered at \(O_1\) and \(O_2\) have radii of equal length. If \(O_1O_2=9\) and AB=3, what is the circumference of the circle centered at \(O_1\) ?
A. 6π
B. 9π
C. 12π
D. 18π
E. 36π
Re: In the figure above, the circles centered at O1 and O2 have
[#permalink]
18 May 2020, 21:23
18 May 2020, 21:23
1
1
O1O2 - AB = O1A + BO2 = 9-3 = 6
Circles are of same radius, O1A = BO2 = 3
The radius of Circle: O1A + AB = 3+3 = 6
Circumference: 2π*radius = 2π*6 = 12π
Circles are of same radius, O1A = BO2 = 3
The radius of Circle: O1A + AB = 3+3 = 6
Circumference: 2π*radius = 2π*6 = 12π
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: In the figure above, the circles centered at O1 and O2 have
[#permalink]
19 May 2020, 05:49
19 May 2020, 05:49
3
Carcass wrote:
Attachment:
#greprepclub In the figure above, the circles centered at.jpg
In the figure above, the circles centered at \(O_1\) and \(O_2\) have radii of equal length. If \(O_1O_2=9\) and \(AB=3\), what is the circumference of the circle centered at \(O_1\) ?
A. 6π
B. 9π
C. 12π
D. 18π
E. 36π
Since the two circles are identical, the two lengths below (indicated by x) are the same length.
Let's also let y = the length of AB
Since we're told \(O_1O_2=9\), we can write: x + y + x = 9
Since we're told AB=3, we can write: x + 3 + x = 9
Solve to get x = 3
So the individual lengths are as follows:
This means we can calculate the radius of the circle centered at \(O_1\)
The radius = 3 + 3 = 6
Circumference of circle = 2πr = 2π(6) = 12π
Answer: C
Cheers,
Brent
