• Economist Test Prep
    Free Trial & Practice Exam
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    Economist Test Prep
  • PrepScholar GMAT
    5 Day FREE Trial
    Study Smarter, Not Harder

    Available with Beat the GMAT members only code

    MORE DETAILS
    PrepScholar GMAT
  • Veritas Prep
    Free Veritas GMAT Class
    Experience Lesson 1 Live Free

    Available with Beat the GMAT members only code

    MORE DETAILS
    Veritas Prep
  • Magoosh
    Magoosh
    Study with Magoosh GMAT prep

    Available with Beat the GMAT members only code

    MORE DETAILS
    Magoosh
  • Kaplan Test Prep
    Free Practice Test & Review
    How would you score if you took the GMAT

    Available with Beat the GMAT members only code

    MORE DETAILS
    Kaplan Test Prep
  • EMPOWERgmat Slider
    1 Hour Free
    BEAT THE GMAT EXCLUSIVE

    Available with Beat the GMAT members only code

    MORE DETAILS
    EMPOWERgmat Slider
  • Target Test Prep
    5-Day Free Trial
    5-day free, full-access trial TTP Quant

    Available with Beat the GMAT members only code

    MORE DETAILS
    Target Test Prep
  • e-gmat Exclusive Offer
    Get 300+ Practice Questions
    25 Video lessons and 6 Webinars for FREE

    Available with Beat the GMAT members only code

    MORE DETAILS
    e-gmat Exclusive Offer
  • Varsity Tutors
    Award-winning private GMAT tutoring
    Register now and save up to $200

    Available with Beat the GMAT members only code

    MORE DETAILS
    Varsity Tutors

DS-6

This topic has 1 expert reply and 0 member replies
candygal79 Senior | Next Rank: 100 Posts
Joined
10 Feb 2014
Posted:
49 messages
Followed by:
3 members

DS-6

Post Fri Apr 04, 2014 12:52 am
Elapsed Time: 00:00
  • Lap #[LAPCOUNT] ([LAPTIME])
    In isosceles RST what is measure of < R

    1) the measure of <T is 100

    2) the measure of < S is 40

    Need free GMAT or MBA advice from an expert? Register for Beat The GMAT now and post your question in these forums!
    Post Fri Apr 04, 2014 1:31 am
    candygal79 wrote:
    In isosceles RST, what is measure of ∠R?

    1) ∠T = 100 degrees
    2) ∠S = 40 degrees
    IMPORTANT: In an isosceles triangle there are 2 IDENTICAL angles, and 1 LONE angle.

    Target question: What is measure of ∠R?

    Statement 1: ∠T = 100 degrees
    We should recognize that ∠T CANNOT be one of the identical angles. If this were the case, we'd have two angles with measures of 100 degrees each, which would result in a triangle in which the sum of the angles is GREATER than 180 degree (which is IMPOSSIBLE)
    So, we can conclude that ∠T must be the LONE angle, which means ∠R and ∠S are the two IDENTICAL angles.
    Since the sum of the 3 angles must be 180, we can conclude that ∠R = 40, ∠S = 40, and ∠T = 100
    Since we can answer the target question with certainty, statement 1 is SUFFICIENT

    Statement 2: ∠S = 40 degrees
    Here are two possible cases to consider:
    Case a: ∠S is the LONE angle, in which case the ∠R = 70, ∠S = 40, and ∠T = 70
    Case b: ∠S is one of the IDENTICAL angles, in which case we could have ∠R = 40, ∠S = 40, and ∠T = 100
    Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

    Answer = A

    Cheers,
    Brent

    _________________
    Brent Hanneson – Founder of GMATPrepNow.com
    Use our video course along with Beat The GMAT's free 60-Day Study Guide

    Check out the online reviews of our course

    GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMAT’s FREE 60-Day Study Guide and reach your target score in 2 months!

    Best Conversation Starters

    1 Vincen 180 topics
    2 lheiannie07 61 topics
    3 Roland2rule 61 topics
    4 ardz24 40 topics
    5 VJesus12 14 topics
    See More Top Beat The GMAT Members...

    Most Active Experts

    1 image description Brent@GMATPrepNow

    GMAT Prep Now Teacher

    160 posts
    2 image description Rich.C@EMPOWERgma...

    EMPOWERgmat

    102 posts
    3 image description GMATGuruNY

    The Princeton Review Teacher

    99 posts
    4 image description Jay@ManhattanReview

    Manhattan Review

    86 posts
    5 image description Matt@VeritasPrep

    Veritas Prep

    80 posts
    See More Top Beat The GMAT Experts