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

Diffcult geometry problem!

Expert replies
Post new topic Post Reply
Subscribe topic
Previous Topic Next Topic
User avatar
Master | Next Rank: 500 Posts
Posts: 100
Joined: Wed Jul 30, 2008 9:52 am
Thanked: 4 times
by ashish1354 » Sun Nov 16, 2008 2:20 am
A triangle ABC is drawn to circumscribe a circle of radius 4 cm such that the segments BD and DC into which BC is divided by the point of contact D are of lengths 6cm & 8 cm respectively (see figure in file attached). Find sides AB and AC.
You do not have the required permissions to view the files attached to this post.
Top
Join the discussion
Source: — Problem Solving |
User avatar
Legendary Member
Posts: 2134
Joined: Mon Oct 20, 2008 11:26 pmFollowed by: 25 members
Thanked: 237 times
GMAT Score:730

Re: Diffcult geometry problem!

by logitech » Sun Nov 16, 2008 3:01 am
ashish1354 wrote:A triangle ABC is drawn to circumscribe a circle of radius 4 cm such that the segments BD and DC into which BC is divided by the point of contact D are of lengths 6cm & 8 cm respectively (see figure in file attached). Find sides AB and AC.
This question has been around for centuries :)

https://en.wikipedia.org/wiki/Incircle

AB and AC can be found as 13 and 15 but it takes some serious calculation, if you really want to know incircles, you can take a look at the wikipedia link but I don't think that this question is within the scope of GMAT's geometry questions.
LGTCH
---------------------
"DON'T LET ANYONE STEAL YOUR DREAM!"
Top
Join the discussion
Legendary Member
Posts: 683
Joined: Tue Jul 22, 2008 1:58 pmFollowed by: 2 members
Location: Dubai
Thanked: 73 times

by mals24 » Sun Nov 16, 2008 5:15 am
Agree with logitech

The calculations involve the use of trigonometry and this concept is not tested in GMAT (Thankfully!!)
Top
Join the discussion
Legendary Member
Posts: 940
Joined: Tue Aug 26, 2008 3:22 amFollowed by: 1 member
Thanked: 55 times

Re: Diffcult geometry problem!

by iamcste » Sun Nov 16, 2008 5:41 am
ashish1354 wrote:A triangle ABC is drawn to circumscribe a circle of radius 4 cm such that the segments BD and DC into which BC is divided by the point of contact D are of lengths 6cm & 8 cm respectively (see figure in file attached). Find sides AB and AC.

source pls...
Top
Join the discussion
User avatar
Legendary Member
Posts: 871
Joined: Wed Aug 13, 2008 7:48 am
Thanked: 48 times

by stop@800 » Sun Nov 16, 2008 5:58 am
I am getting 6*sqrt(3) and 6*sqrt(5).

OA please
Top
Join the discussion
User avatar
Master | Next Rank: 500 Posts
Posts: 100
Joined: Wed Jul 30, 2008 9:52 am
Thanked: 4 times

answers!

by ashish1354 » Mon Nov 17, 2008 12:58 am
AC=13
AB=15

and the answer can also be calculated without trignometry :P
Top
Join the discussion
User avatar
Master | Next Rank: 500 Posts
Posts: 100
Joined: Wed Jul 30, 2008 9:52 am
Thanked: 4 times

source

by ashish1354 » Mon Nov 17, 2008 1:05 am
its a xth standard circles and tangents problem
Top
Join the discussion
Legendary Member
Posts: 683
Joined: Tue Jul 22, 2008 1:58 pmFollowed by: 2 members
Location: Dubai
Thanked: 73 times

by mals24 » Mon Nov 17, 2008 4:55 am
Ok another method of solving this would be by using the Heron's formula, semi perimeter and incircle (thats what I think would be the method used in the book as well if its a CBSE book). These methods again are thankfully not required for the GMAT :)

semi perimeter s = (a+b+c)/2 = 14+x
Area of triangle = rs
= 4(14+x) = 56+4x.
Area of triangle = 1/2bh = 1/2*14*AD = 7AD

AD = AO + OD = AO +4
Area = 7(AO+4) = 7AO + 28
Equate the 2 areas: 7AO+28 = 56+4X--equ 1
AO = x^2 + 16 (pythagoras theorem).
Sustitute AO in equation 1 and youll get x = 6.79 or 7 approx

AB = 13 AC = 15

Im glad CBSE is not making the quant section of GMAT :)
Top
Join the discussion