Last visit was: 24 Apr 2026, 08:05 It is currently 24 Apr 2026, 08:05
Home
Messages
Tests
Schools
Events
Close
GMAT Club Daily Prep
Thank you for using the timer - this advanced tool can estimate your performance and suggest more practice questions. We have subscribed you to Daily Prep Questions via email.

Customized
for You

we will pick new questions that match your level based on your Timer History

Track
Your Progress

every week, we’ll send you an estimated GMAT score based on your performance

Practice
Pays

we will pick new questions that match your level based on your Timer History
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
Go to My Error Log Learn more
Close
Request Expert Reply
Confirm Cancel
Back to Forum
Create Topic
Sub 505 (Easy)|   Geometry|      
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
20,000
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
If a right triangle has 2x and 2x+1, what is the length of BC, in term 21 Feb 2016, 22:05
Kudos
Add Kudos
Bookmarks
Bookmark this Post
00:00
Start Timer
Pause Timer
Resume Timer
Show Answer
Hide
Show
History
D
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!

Difficulty:

5% (low)

Question Stats:

80% (01:00) correct 20% (01:08) wrong based on 112 sessions

History

Date
Time
Result
Not Attempted Yet
Attachment:
a right triangle.jpg
a right triangle.jpg [ 5 KiB | Viewed 2777 times ]
If a right triangle has 2x and 2x+1, what is the length of BC, in terms of x?

A. 4x-1
B. 4x+1
C. √(4x-1)
D. √(4x+1)
E. 4x


* A solution will be posted in two days.
ShowHide Answer
Official Answer
D
User avatar
CounterSniper
User avatar
Joined: 20 Feb 2015
Last visit: 14 Apr 2023
Posts: 611
Own Kudos:
859
Given Kudos: 74
Concentration: Strategy, General Management
Posts: 611
Kudos: 859
If a right triangle has 2x and 2x+1, what is the length of BC, in term 22 Feb 2016, 06:50
Kudos
Add Kudos
Bookmarks
Bookmark this Post
using pythagoras theorem we have
(BC)2 =(AC)2-(AB)2
BC = root(4x+1)
User avatar
davedekoos
User avatar
Joined: 09 Jul 2013
Last visit: 07 Nov 2025
Posts: 96
Own Kudos:
347
Given Kudos: 11
Posts: 96
Kudos: 347
If a right triangle has 2x and 2x+1, what is the length of BC, in term 22 Feb 2016, 10:29
Kudos
Add Kudos
Bookmarks
Bookmark this Post
CounterSniper
using pythagoras theorem we have
(BC)2 =(AC)2-(AB)2
BC = root(4x+1)
Show more


CounterSniper nailed it. Here it is with the proper formatting:

\((AC)^2 = (AB)^2 + (BC)^2\)
\((2x+1)^2 = (2x)^2 + (BC)^2\)
\(4x^2 + 4x+ 1 = 4x^2 + (BC)^2\)
\((BC)^2 = 4x+1\)
\(BC = \sqrt{4x+1}\)

Answer: D
User avatar
ENGRTOMBA2018
User avatar
Joined: 20 Mar 2014
Last visit: 01 Dec 2021
Posts: 2,319
Own Kudos:
3,890
Given Kudos: 816
Concentration: Finance, Strategy
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
GPA: 3.7
WE:Engineering (Aerospace and Defense)
Products:
My Reviews
Schools: Kellogg '18 (M)
GMAT 1: 750 Q49 V44
Posts: 2,319
Kudos: 3,890
If a right triangle has 2x and 2x+1, what is the length of BC, in term 22 Feb 2016, 10:51
Kudos
Add Kudos
Bookmarks
Bookmark this Post
davedekoos
CounterSniper
using pythagoras theorem we have
(BC)2 =(AC)2-(AB)2
BC = root(4x+1)


CounterSniper nailed it. Here it is with the proper formatting:

\((AC)^2 = (AB)^2 + (BC)^2\)
\((2x+1)^2 = (2x)^2 + (BC)^2\)
\(4x^2 + 4x+ 1 = 4x^2 + (BC)^2\)
\((BC)^2 = 4x+1\)
\(BC = \sqrt{4x+1}\)

Answer: D
Show more

An alternate way would be to substitute x=1 to get the 2 given sides as 2x=2 units and 2x+1=9, giving you the other side = \(\sqrt{9-4}\) = \(\sqrt{5}\)

Analyse options,

A. 4x-1 = 3 . Eliminate
B. 4x+1 = 5. Eliminate
C. √(4x-1) = \(\sqrt{3}\). Eliminate
D. √(4x+1) =\(\sqrt{5}\). Keep.
E. 4x= 4. Eliminate.

Thus D is the correct answer.

Hope this helps.
User avatar
MathRevolution
User avatar
Math Revolution GMAT Instructor
Joined: 16 Aug 2015
Last visit: 27 Sep 2022
Posts: 10,063
Own Kudos:
20,000
Given Kudos: 4
GMAT 1: 760 Q51 V42
GPA: 3.82
Expert
Expert reply
GMAT 1: 760 Q51 V42
Posts: 10,063
Kudos: 20,000
If a right triangle has 2x and 2x+1, what is the length of BC, in term 23 Feb 2016, 18:35
Kudos
Add Kudos
Bookmarks
Bookmark this Post
If a right triangle has 2x and 2x+1, what is the length of BC, in terms of x?

A. 4x-1
B. 4x+1
C. √(4x-1)
D. √(4x+1)
E. 4x


-> (2x)2+(BC)2=(2x+1)2, (BC)2=4x2+4x+1-4x2=4x+1, BC=√(4x+1). Therefore, the answer is D.
Moderators:
Bunuel
Math Expert
109814 posts
Krunaal
Tuck School Moderator
853 posts