Can anyone help me solve this problem?
As the figure above shows, two circles lie on a line and tangent to each other. If the radius of two circles are 2r and r, respectively, in terms of r, AB=?
(A) 5r/2
(B) 8r/3
(C) 2*2^1/2*r
(D) 3r
(E) 2*3^1/2*r
Pls find the figure in the attached doc.
Thanks for your help.
Math Problem - Help needed to solve
This topic has expert replies
-
- Junior | Next Rank: 30 Posts
- Posts: 13
- Joined: Tue Mar 16, 2010 12:53 pm
- Attachments
-
- Doc1.docx
- (14.16 KiB) Downloaded 113 times
Last edited by priyasaibaba on Wed Apr 21, 2010 7:44 am, edited 3 times in total.
- eaakbari
- Master | Next Rank: 500 Posts
- Posts: 435
- Joined: Mon Mar 15, 2010 6:15 am
- Thanked: 32 times
- Followed by:1 members
Do attach the figure, you will not be able to paste it. I cannot understand the figure solely through your explanation
Whether you think you can or can't, you're right.
- Henry Ford
- Henry Ford
-
- Junior | Next Rank: 30 Posts
- Posts: 13
- Joined: Tue Mar 16, 2010 12:53 pm
-
- Junior | Next Rank: 30 Posts
- Posts: 13
- Joined: Tue Mar 16, 2010 12:53 pm
- eaakbari
- Master | Next Rank: 500 Posts
- Posts: 435
- Joined: Mon Mar 15, 2010 6:15 am
- Thanked: 32 times
- Followed by:1 members
-
- Junior | Next Rank: 30 Posts
- Posts: 13
- Joined: Tue Mar 16, 2010 12:53 pm
- Stuart@KaplanGMAT
- GMAT Instructor
- Posts: 3225
- Joined: Tue Jan 08, 2008 2:40 pm
- Location: Toronto
- Thanked: 1710 times
- Followed by:614 members
- GMAT Score:800
Great job!
You ended up with the correct answer, just want to correct one small typo so no one gets confused along the way:
9(r^2) is actually the hypotenuse, not ED^2, so that should be:ED^2 = 9r^2 + r^2
ED^2 = 9(r^2) - r^2
You did the math as though it were a subtraction sign, so all is good after that point!
Stuart Kovinsky | Kaplan GMAT Faculty | Toronto
Kaplan Exclusive: The Official Test Day Experience | Ready to Take a Free Practice Test? | Kaplan/Beat the GMAT Member Discount
BTG100 for $100 off a full course