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
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.

Area of Right angle Triangle (DS)

Expert replies
Post new topic Post Reply
Previous Topic Next Topic
Source: — Data Sufficiency |

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 2095
Joined: Tue Dec 04, 2012 3:22 pmFollowed by: 247 members
Thanked: 1443 times

by ceilidh.erickson » Sat Apr 12, 2014 1:21 pm
In order to find the area of a triangle, we need the base and the height. For a right triangle, that means the lengths of both the two non-hypotenuse sides.

Statements (1) and (2) are clearly insufficient on their own, as each gives us only a single side length, and we need both the base and the height.

Be careful, though! That doesn't mean that using the statement together will give us the area. This question is trying to trick us into thinking that we have a familiar right triangle: 9-12-15, giving us an area of 54.

That's one possibility, but it's also possible that 9 and 15 are the base and height, and the hypotenuse is sqrt(306). This would give us an area of 67.5.

The answer is E.

Remember that in geometry DS questions, you should try to think of as many configurations of the given shape as possible - don't just assume that it's the familiar one.
Ceilidh Erickson
EdM in Mind, Brain, and Education
Harvard Graduate School of Education
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

Area of Right angle Triangle (DS)

by Brent@GMATPrepNow » Sat Apr 12, 2014 1:27 pm
ajaysingh24 wrote:What is the area of right triangle XYZ?

(1) Side YZ is 9 inches long.
(2) Side XZ is 15 inches long.
Target question: What is the area of right triangle XYZ?

KEY CONCEPT: Area of triangle = (1/2)(base)(height)
So, to answer the target question, we need lengths of BOTH the base AND the height.

Statement 1: Side YZ is 9 inches long.
We have only 1 measurement. So, there's no way to determine the area of the triangle.
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: Side XZ is 15 inches long.
We have only 1 measurement. So, there's no way to determine the area of the triangle.
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
We still don't have enough information.
Consider the following 2 cases (which both satisfy the given conditions).

case a:
Image
Here, the area = (1/2)(9)(12) = 54

case b:
Image
Here, the area = (1/2)(9)(15)= 67.5
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E

Cheers,
Brent
Last edited by Brent@GMATPrepNow on Sun Apr 29, 2018 5:19 am, edited 1 time in total.
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 641
Joined: Tue Feb 14, 2012 3:52 pmFollowed by: 8 members
Thanked: 11 times

by gmattesttaker2 » Sun Jun 22, 2014 6:04 pm
Brent@GMATPrepNow wrote:
ajaysingh24 wrote:What is the area of right triangle XYZ?

(1) Side YZ is 9 inches long.
(2) Side XZ is 15 inches long.
Target question: What is the area of right triangle XYZ?

KEY CONCEPT: Area of triangle = (1/2)(base)(height)
So, to answer the target question, we need lengths of BOTH the base AND the height.

Statement 1: Side YZ is 9 inches long.
We have only 1 measurement. So, there's no way to determine the area of the triangle.
Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT

Statement 2: Side XZ is 15 inches long.
We have only 1 measurement. So, there's no way to determine the area of the triangle.
Since we cannot answer the target question with certainty, statement 2 is NOT SUFFICIENT

Statements 1 and 2 combined
We still don't have enough information.
Consider the following 2 cases (which both satisfy the given conditions).

case a:
Image
Here, the area = (1/2)(9)(12) = 54

case b:
Image
Here, the area = (1/2)(9)(15)= 67.5
Since we cannot answer the target question with certainty, the combined statements are NOT SUFFICIENT

Answer = E

Cheers,
Brent

Hello Brent,

Thanks for the explanation. Suppose we have a right angled triangle where we are given the value of the hypotenuse only and are asked to determine the value of the other two sides, is it possible to determine those values? For example, if the hypotenuse of a right triangle is 5, then I think we can say for sure that the value of the other 2 sides are 3 and 2. Can we do this for any right triangle if we know the hypotenuse? Thanks a lot for your help.

Best Regards,
Sri

I could be wrong but I think I have come across triangles hwere
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY

GMAT/MBA Expert

User avatar
GMAT Instructor
Posts: 16207
Joined: Mon Dec 08, 2008 6:26 pmFollowed by: 1268 members
Location: Vancouver, BC
Thanked: 5254 times
GMAT Score:770

by Brent@GMATPrepNow » Sun Jun 22, 2014 6:32 pm
gmattesttaker2 wrote: Hello Brent,

Thanks for the explanation. Suppose we have a right angled triangle where we are given the value of the hypotenuse only and are asked to determine the value of the other two sides, is it possible to determine those values? For example, if the hypotenuse of a right triangle is 5, then I think we can say for sure that the value of the other 2 sides are 3 and 2. Can we do this for any right triangle if we know the hypotenuse? Thanks a lot for your help.

Best Regards,
Sri

I could be wrong but I think I have come across triangles hwere
If we know the length of the hypotenuse only, then we can't find the other two lengths.
For example, if the hypotenuse has length 5 and the other two sides have lengths x and y, all we can say for certain is that x² + y² = 5² (by the Pythagorean Theorem)
There is an infinite number of solutions to this equation. Here are just a few:
x = 3 and y = 4
x = √11 and y = √14
x = √8 and y = √17
x = 2 and y = √21
etc.

Cheers,
Brent
Brent Hanneson - Creator of GMATPrepNow.com
Image
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Legendary Member
Posts: 641
Joined: Tue Feb 14, 2012 3:52 pmFollowed by: 8 members
Thanked: 11 times

by gmattesttaker2 » Sun Jun 22, 2014 8:21 pm
Brent@GMATPrepNow wrote:
gmattesttaker2 wrote: Hello Brent,

Thanks for the explanation. Suppose we have a right angled triangle where we are given the value of the hypotenuse only and are asked to determine the value of the other two sides, is it possible to determine those values? For example, if the hypotenuse of a right triangle is 5, then I think we can say for sure that the value of the other 2 sides are 3 and 2. Can we do this for any right triangle if we know the hypotenuse? Thanks a lot for your help.

Best Regards,
Sri

I could be wrong but I think I have come across triangles hwere
If we know the length of the hypotenuse only, then we can't find the other two lengths.
For example, if the hypotenuse has length 5 and the other two sides have lengths x and y, all we can say for certain is that x² + y² = 5² (by the Pythagorean Theorem)
There is an infinite number of solutions to this equation. Here are just a few:
x = 3 and y = 4
x = √11 and y = √14
x = √8 and y = √17
x = 2 and y = √21
etc.

Cheers,
Brent

Hello Brent,

Thanks a lot for the clarification.

Best Regards,
Sri
Top
Join the discussion
Log in to postLogin with Googleuse password
QUOTE IN REPLY
Post new topic Post Reply
• Page 1 of 1