BREAKING: Target Test Prep releases Brand New 2026 On Demand GMAT prep course

Redeem

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.

★★★★★5.0559 reviews
Vote for Target Test Prep, Newsweek Readers’ Choice Awards 2026
NEWSWEEK READERS’ CHOICE 2026

BIG NEWS! Target Test Prep has been nominated, and they’d love your vote!

TTP has worked incredibly hard to build the best test prep experience possible, and winning Newsweek’s 2026 Readers’ Choice Award for Best Test Prep would mean a lot to them. If TTP has helped you, they’d be incredibly grateful for your vote. You can vote once each day through September 9.

Vote for TTP
GMATLiveTeach 7 seats left
Chris Peckover
NEXT LIVE COHORT

Oct 13 to Jan 7, 2027

with Chris Peckover

Schedule
Tue, Thu · 8:00 to 10:00 PM ET
Included
40 live hours + 6 months of GMAT OnDemand
  • Live instruction and real-time questions
  • Class recordings and assigned practice
View class & enroll
Limited cohort · enrollment openTarget Test Prep
EALiveTeach 5 seats left
Logan Thompson
EXECUTIVE ASSESSMENT

Sep 6 to Dec 6, 2026

with Logan Thompson

Schedule
Sun · 9:30 AM to 12:30 PM ET
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
Limited cohort · enrollment openTarget Test Prep
GMATOnDemand Start 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 559 reviewsTarget Test Prep

Compare the format, schedule, and included access before enrolling. Prices and seat counts shown reflect the supplied offer details.

Interior Angles of a Quadrilateral

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Senior | Next Rank: 100 Posts
Posts: 74
Joined: Fri Oct 09, 2009 4:20 pm
Thanked: 4 times
by nakul_anand » Sun May 02, 2010 5:09 pm
Is the measure of one of the interior angles of the quadrilateral ABCD equal to 60 degrees?

(1) Two of the interior angles of the quadrilateral ABCD are right angles.

(2) The degree measure of angle ABC is twice the degree measure of angle BCD.


[spoiler]OA:E[/spoiler]
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Source: — Data Sufficiency |
Legendary Member
Posts: 576
Joined: Sat Mar 13, 2010 8:31 pmFollowed by: 1 member
Thanked: 97 times

by liferocks » Sun May 02, 2010 5:56 pm
I am getting the ans as C--both together are sufficient

clearly either of the conditions alone is not sufficient.

together , angle CDA =angle DAB =90..hence angle ABC + angle BCD =180
since angle ABC =2*angle BCD ...angle BCD=60

Can someone please explain what is wrong with the approach?
"If you don't know where you are going, any road will get you there."
Lewis Carroll
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Master | Next Rank: 500 Posts
Posts: 268
Joined: Wed Mar 17, 2010 2:32 am
Thanked: 17 times

by this_time_i_will » Sun May 02, 2010 6:11 pm
nakul_anand wrote:Is the measure of one of the interior angles of the quadrilateral ABCD equal to 60 degrees?

(1) Two of the interior angles of the quadrilateral ABCD are right angles.

(2) The degree measure of angle ABC is twice the degree measure of angle BCD.


[spoiler]OA:E[/spoiler]
quite a subtle question.

I: clearly NOT SUFFICIENT.
II: clearly NOT SUFFICIENT.

Both: As shown by liferocks above, one of the angle may be 60 degree or as shown below may not be 60 degree:
Let,
angle ABC = 90.
angle BCD = 45.
angle BAD = 90.
so, ADC = 135.
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 576
Joined: Sat Mar 13, 2010 8:31 pmFollowed by: 1 member
Thanked: 97 times

by liferocks » Sun May 02, 2010 6:14 pm
this_time_i_will wrote:
nakul_anand wrote:Is the measure of one of the interior angles of the quadrilateral ABCD equal to 60 degrees?

(1) Two of the interior angles of the quadrilateral ABCD are right angles.

(2) The degree measure of angle ABC is twice the degree measure of angle BCD.


[spoiler]OA:E[/spoiler]
quite a subtle question.

I: clearly NOT SUFFICIENT.
II: clearly NOT SUFFICIENT.

Both: As shown by liferocks above, one of the angle may be 60 degree or as shown below may not be 60 degree:
Let,
angle ABC = 90.
angle BCD = 45.
angle BAD = 90.
so, ADC = 135.
Got the point..Thanks!
"If you don't know where you are going, any road will get you there."
Lewis Carroll
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1