GRE Prep 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.
In the figure below, If the area of triangle CDE is 42, what
[#permalink]
26 May 2019, 01:46
26 May 2019, 01:46
Expert Reply
12
Bookmarks
In the figure below, AB=BC=CD. If the area of triangle CDE is 42, what is the area of triangle ADG?
#GREexcercise In the figure below, If the area of triangle CDE is 42, what is AB=BC=CD..jpg [ 10.08 KiB | Viewed 55867 times ]
Attachment:
#GREexcercise In the figure below, If the area of triangle CDE is 42, what is AB=BC=CD..jpg [ 10.08 KiB | Viewed 55867 times ]
Show: :: OA
378
Math Review
Question: 9
Page: 260
Difficulty: medium
Question: 9
Page: 260
Difficulty: medium
Retired Moderator
Joined: 10 Apr 2015
Posts: 6218
Given Kudos: 136
Re: In the figure below, If the area of triangle CDE is 42, what
[#permalink]
29 May 2019, 07:55
29 May 2019, 07:55
12
3
Bookmarks
Carcass wrote:
In the figure below, AB=BC=CD. If the area of triangle CDE is 42, what is the area of triangle ADG?
Attachment:
#GREexcercise In the figure below, If the area of triangle CDE is 42, what is AB=BC=CD..jpg
Show: :: OA
378
Math Review
Question: 9
Page: 260
Difficulty: medium
Question: 9
Page: 260
Difficulty: medium
Let's add the given information to the diagram.
Notice that the angles (represented by blue dots) are all equal.
If we draw some auxiliary lines from points B and C....
...we find that we have 3 IDENTICAL right triangles
If we let y = the base of ∆CDE and let x = the height of ∆CDE...
...then we can add several more x's and y's to the diagram.
From this, we can see that...
...the base of ∆ADG has length 3y and a height of 3x
GIVEN: the area of ∆CDE is 42
Area of triangle = (base)(height)/2
So, we can write: (y)(x)/2 = 42
This means: yx = 84
We're asked to find the area of ∆ADG
Area of triangle = (base)(height)/2
So, the area of ∆ADG = (3y)(3x)/2
= 9yx/2
Since we know that yx = 84, we can replace yx with 84 to get:
Area of ∆ADG = 9(84)/2 = 378
Answer: 378
Cheers,
Brent
General Discussion
Re: In the figure below, If the area of triangle CDE is 42, what
[#permalink]
26 May 2019, 19:20
26 May 2019, 19:20
6
Carcass wrote:
In the figure below,AB=BC=CD. If the area of triangle CDE is 42, what is the area of triangle ADG?
Attachment:
#GREexcercise In the figure below, If the area of triangle CDE is 42, what is AB=BC=CD..jpg
Show: :: OA
378
Math Review
Question: 9
Page: 260
Difficulty: medium
Question: 9
Page: 260
Difficulty: medium
Here,
all the three triangles ( \(\triangle\)CDE , \(\triangle\) BDF and \(\triangle\) ADG are similar)
and one side of the \(\triangle\) CDE = \(\frac{1}{3}\)of the \(\triangle\) ADG
Hence the Area of \(\triangle\)ADG = \((\frac{1}{2} * AG * DG) = (\frac{1}{2} * 3CE * 3DE) = 9 * (\frac{1}{2} * CE * DE)\) = 9 * Area of the \(\triangle\) CDE = \(9 * 42 = 378\)
