|
|
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
Track
Your Progress
Practice
Pays
Not interested in getting valuable practice questions and articles delivered to your email? No problem, unsubscribe here.
01 Aug 2017, 04:39
Kudos
Bookmarks
C
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:
84% (00:36) correct
16%
(00:39)
wrong
based on 68
sessions
History
Date
Time
Result
Not Attempted Yet
In the figure above, when ray OA is rotated clockwise 9 degrees about point O, then it will be perpendicular to ray OB. What is the measure of ∠AOB before rotation?
(A) 81°
(B) 89°
(C) 99°
(D) 93°
(E) 90°
Attachment:
2017-08-01_1347_002.png [ 4.3 KiB | Viewed 3504 times ]
06 Aug 2017, 12:03
Kudos
Bookmarks
Bunuel
Attachment:
ray-angle-change.png [ 17.98 KiB | Viewed 3066 times ]
If need be, draw the end result (in diagram, where OA is red) to track on ray's movement.
Original ray OA is rotated clockwise 9 degrees: it moves from left to right 9 degrees.
Measure of ∠AOB before rotation? It "shrank." So add: 90 + 9 = 99 degrees.
Answer C
You can do this problem with compass (absolute bearing and relative bearing) or clock angles; IMO, unnecessarily complicated. YMMV.
Edited for a typo that created a grammatical mistake which could cause problems in SC. Answer remains the same.
