Last visit was: 24 Apr 2026, 13:15 It is currently 24 Apr 2026, 13:15
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
655-705 (Hard)|   Geometry|      
User avatar
Bunuel
User avatar
Math Expert
Joined: 02 Sep 2009
Last visit: 24 Apr 2026
Posts: 109,820
Own Kudos:
811,062
 [6]
Given Kudos: 105,873
Products:
GMAT Club Tests Forum Quiz
Expert
Expert reply
Active GMAT Club Expert! Tag them with @ followed by their username for a faster response.
Posts: 109,820
Kudos: 811,062
 [6]
In the figure above, what is the average (arithmetic mean) degree meas 24 Aug 2017, 23:46
2
Kudos
Add Kudos
4
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:

55% (hard)

Question Stats:

57% (02:00) correct 43% (01:24) wrong based on 110 sessions

History

Date
Time
Result
Not Attempted Yet

In the figure above, what is the average (arithmetic mean) degree measure of the 12 marked angles?

(A) 40
(B) 50
(C) 60
(D) 70
(E) cannot be determined from the given information


Show Spoiler
Attachment:
2017-08-25_1041_001.png
2017-08-25_1041_001.png [ 18.09 KiB | Viewed 5470 times ]
ShowHide Answer
Official Answer
D
User avatar
septwibowo
User avatar
Joined: 27 Dec 2016
Last visit: 05 Nov 2025
Posts: 189
Own Kudos:
196
Given Kudos: 285
Concentration: Marketing, Social Entrepreneurship
Schools: Yale '21 HBS '21 Darden '21 Wharton '21
GPA: 3.65
WE:Marketing (Education)
Products:
My Reviews
Schools: Yale '21 HBS '21 Darden '21 Wharton '21
Posts: 189
Kudos: 196
In the figure above, what is the average (arithmetic mean) degree meas 25 Aug 2017, 11:12
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Bunuel

In the figure above, what is the average (arithmetic mean) degree measure of the 12 marked angles?

(A) 40
(B) 50
(C) 60
(D) 70
(E) cannot be determined from the given information


Show Spoiler
Attachment:
2017-08-25_1041_001.png
Show more

- Total angles who meet in the centre should be 360-120 = 240.
- IF we assume that the centre angle of each triangle IS SAME, we can calculate the average.
- However, we can assume anything from given picture, so we can calculate.

E.

Waiting great explanation from Bunuel
User avatar
pushpitkc
User avatar
Joined: 26 Feb 2016
Last visit: 19 Feb 2025
Posts: 2,800
Own Kudos:
6,235
 [4]
Given Kudos: 47
Location: India
GPA: 3.12
Posts: 2,800
Kudos: 6,235
 [4]
In the figure above, what is the average (arithmetic mean) degree meas 25 Aug 2017, 11:21
3
Kudos
Add Kudos
1
Bookmarks
Bookmark this Post



Let's call the point of intersection of the 6 triangles O, around which the sum of the angles is 360.
Since, the angle given is 120 degree, the remainder of the angles is 240.

There are 6 triangles and the angle(in each of the 6 triangles around point O) is \(\frac{240}{6} = 40\)
Since the sum of angles in a triangle is 180, the sum of the other 2 angles in each of the triangles is 140.

Therefore, the average degree measure is \(\frac{140*6}{12} =\) 70(Option D)
avatar
lostnumber
avatar
Joined: 28 Mar 2018
Last visit: 22 May 2018
Posts: 38
Own Kudos:
8
Given Kudos: 20
Posts: 38
Kudos: 8
In the figure above, what is the average (arithmetic mean) degree meas 20 Apr 2018, 10:47
Kudos
Add Kudos
Bookmarks
Bookmark this Post
We know that a full circle on a flat plane is 360 degrees.
Since 120 degrees are accounted for the total for the centerpoint angles on the 6 triangles shown must be 240
240/6= 40
Therefore we know that on average one angle of each of the triangles is 40.
Because triangle angles must sum to 180, we know that on average the sum of the other two angles for each triangle is 140. Divide 140 by 2 angles and we can say that on average, the listed angles are 70 degrees!
User avatar
Hero8888
User avatar
Joined: 29 Dec 2017
Last visit: 14 Apr 2019
Posts: 299
Own Kudos:
348
Given Kudos: 273
Location: United States
Concentration: Marketing, Technology
GMAT 1: 630 Q44 V33
GMAT 2: 690 Q47 V37
GMAT 3: 710 Q50 V37
GPA: 3.25
WE:Marketing (Telecommunications)
GMAT 3: 710 Q50 V37
Posts: 299
Kudos: 348
In the figure above, what is the average (arithmetic mean) degree meas 20 Apr 2018, 12:39
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Sum of angles of heptagon (7 sided polygon) = 180*(7-2)= 900
Sum of 2 angles of the triangle x+y= 180-120 = 60, so the sum of rest 12 angles = 900-60 = 840 and Av = 840/12 = 70

Answer (D)
Attachments

2017-08-25_1041_001.png
2017-08-25_1041_001.png [ 18.91 KiB | Viewed 3694 times ]

User avatar
rocky620
User avatar
Retired Moderator
Joined: 10 Nov 2018
Last visit: 11 May 2023
Posts: 481
Own Kudos:
625
 [1]
Given Kudos: 229
Location: India
Concentration: General Management, Strategy
Schools: IIMA PGPX'22 IIMB EPGP'22 IIMC PGPEX'22 ISB'22
GMAT 1: 590 Q49 V22
WE:Other (Retail: E-commerce)
Schools: IIMA PGPX'22 IIMB EPGP'22 IIMC PGPEX'22 ISB'22
GMAT 1: 590 Q49 V22
Posts: 481
Kudos: 625
 [1]
In the figure above, what is the average (arithmetic mean) degree meas 13 May 2019, 04:17
1
Kudos
Add Kudos
Bookmarks
Bookmark this Post
Since there are 6 triangles total degree measure will be 180*6=1080.
total measure of central angles of all triangles is 240.

So remaining angles will be 1080-240=840

Average = 840/12=70.
User avatar
Vinit800HBS
User avatar
Joined: 29 Dec 2018
Last visit: 24 Apr 2026
Posts: 90
Own Kudos:
244
Given Kudos: 195
Location: India
Schools: HBS '22 Wharton '22 Stanford '22
GRE 1: Q170 V163
Expert
Expert reply
Schools: HBS '22 Wharton '22 Stanford '22
GRE 1: Q170 V163
Posts: 90
Kudos: 244
In the figure above, what is the average (arithmetic mean) degree meas 13 May 2019, 04:22
Kudos
Add Kudos
Bookmarks
Bookmark this Post
There are 6 triangles.

Total degree measure is 180*6=1080.
The given angle at the centre is 120 degrees. Do, the remaining angle at the centre is 360-120 = 240

This central angle of 240 alongwith the 12 marked angles form the total measure of 1080.

So remaining angles will be 1080-240=840

Average = 840/12=70.

Posted from my mobile device
Moderators:
Bunuel
Math Expert
109820 posts
Krunaal
Tuck School Moderator
853 posts