Events & Promotions
|
|
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.
Sep 1507:00 PM EDT
-09:00 PM EST
Elite scores are possible when you enroll in a powerful GMAT course, taught live online + 6 months access to TTP OnDemand video courses included! Class starts Tues/Thurs Sept. 15, 2026 - Nov. 15, 2027, 7:00pm-9:00pm EST
Sep 2107:00 PM EDT
-10:00 PM EDT
Boost your GMAT score in less than one month in a live online class + 6 months access to TTP OnDemand video courses included! Class starts Mon, Tues, Wed, Thur, Fri Sept. 21, 2026 - Oct. 9, 2027, 7:00pm-10:00pm EST
03 Dec 2018, 07:24
Kudos
Bookmarks
E
Be sure to select an answer first to save it in the Error Log before revealing the correct answer (OA)!
Difficulty:
15%
(low)
Question Stats:
83% (01:39) correct
17%
(02:06)
wrong
based on 516
sessions
History
Date
Time
Result
Not Attempted Yet
In the figure above, square CDEF has area 4. What is the area of △ ABF?
(A) 2\(\sqrt{2}\)
(B) 2\(\sqrt{3}\)
(C) 4
(D) 3\(\sqrt{3}\)
(E) 6
Attachment:
ABF.JPG [ 19.41 KiB | Viewed 9663 times ]
Every tricky question should trigger a follow up quiz.
Build that habit with
GMAT Club Forum Quiz →.
03 Dec 2018, 10:48
Kudos
Bookmarks
IMO E
Triangle \(CFB\) is a 30-60-90 triangle, therefore is side \(FB=2*\sqrt{3}\)...
Triangle \(ABF\) is a 45-45-90 triangle (isosceles right triangle), therefore is side \(BF=AB\) and the hypotenuse is equal to \(2*\sqrt{3}*\sqrt{2}\)
Area of \(ABF=\) \(\frac{1}{2}*2*\sqrt{3}*2*\sqrt{3}=\)\(6\)
Triangle \(CFB\) is a 30-60-90 triangle, therefore is side \(FB=2*\sqrt{3}\)...
Triangle \(ABF\) is a 45-45-90 triangle (isosceles right triangle), therefore is side \(BF=AB\) and the hypotenuse is equal to \(2*\sqrt{3}*\sqrt{2}\)
Area of \(ABF=\) \(\frac{1}{2}*2*\sqrt{3}*2*\sqrt{3}=\)\(6\)
Attachments
Screen Shot 2018-12-03 at 18.36.52.png [ 134.78 KiB | Viewed 9203 times ]
General Discussion
17 Jan 2019, 12:33
Kudos
Bookmarks
HKD1710
If the area of the square is 4, then each side has length 2
At this point, we have a special 30-60-90 right triangle. When we compare this blue triangle to the BASE 30-60-90 right triangle . . .
. . . we see that the blue triangle TWICE the size of the BASE 30-60-90 right triangle
So, These are the measurements of the blue triangle
Finally, we have special 45-45-90 right triangle.
This triangle is also an ISOSCELES triangle, so the other side ALSO has length 2√3
What is the area of △ABF?
area of a triangle = (base)(height)/2
So, area of △ABF = (2√3)(2√3)/2
= (4√9)/2
= (4)(3)/2
= 12/2
= 6
Answer: E
Cheers,
Brent
