Angle BDC = Angle BCD = 2x
=> Triangle BDC is isosceles
=> BD = BC --------------(1)
In a triangle, exterior angle is equal to the sum of interior angles.
So, Angle BDC = Angle Angle ABD + Angle BAD
=> 2x = Angle ABD + x
=> Angle ABD = x
=> Triangle ABD is isosceles
=> AD = BD --------------(1)
From (1) and (2)
AD = BD = BC ------------(3)
Q. What is BC?
Statement 1
AD = 6
=> BC = 6 (From 3)
Sufficient.
Statement 2
x=36.
This itself is insufficient as AD can take any value without disturbing the angle.
Insufficient.
Answer A
Triangle problem
This topic has expert replies
Source: Beat The GMAT — Data Sufficiency |
thank you for this:
In a triangle, exterior angle is equal to the sum of interior angles.
So, Angle BDC = Angle Angle ABD + Angle BAD
will have to review that section of the Geometry curriculum.
Thanks again!
In a triangle, exterior angle is equal to the sum of interior angles.
So, Angle BDC = Angle Angle ABD + Angle BAD
will have to review that section of the Geometry curriculum.
Thanks again!
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To determine how the angles in a figure affect each other, plug in for the angle measurements, following the rules of geometry and the conditions given in the problem:
The drawings above show two combinations of angles that follow both the rules of geometry and the conditions given in the problem.
In each case, AD = BD = BC.
Question rephrased: What is the length of AD or BD?
Statement 1: AD = 6.
Sufficient.
Statement 2: x=36.
No information about the any of the lengths.
Insufficient.
The correct answer is A.
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venmic
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Hi -
I do not understand how is AD = BD = BC
I understand how AD = BD but NOT how it is equal to BC from the angles.
Even from the picture I dont see how it is equal
Appreciate it if you can explain
Thanks
I do not understand how is AD = BD = BC
I understand how AD = BD but NOT how it is equal to BC from the angles.
Even from the picture I dont see how it is equal
Appreciate it if you can explain
Thanks
GMATGuruNY wrote:
To determine how the angles in a figure affect each other, plug in for the angle measurements, following the rules of geometry and the conditions given in the problem:
The drawings above show two combinations of angles that follow both the rules of geometry and the conditions given in the problem.
In each case, AD = BD = BC.
Question rephrased: What is the length of AD or BD?
Statement 1: AD = 6.
Sufficient.
Statement 2: x=36.
No information about the any of the lengths.
Insufficient.
The correct answer is A.
-
GMATGuruNY
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- Joined: Tue May 25, 2010 12:04 pm
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venmic wrote:Hi -
I do not understand how is AD = BD = BC
I understand how AD = BD but NOT how it is equal to BC from the angles.
Even from the picture I dont see how it is equal
Appreciate it if you can explain
Thanks
In each of the drawings above:
In ∆ABD, ∠BAD = ∠ABD. Thus, AD = BD.
In ∆BCD, ∠BDC = ∠BCD. Thus, BD = BC.
Since AD = BD and BD = BC, we know that AD = BD = BC.
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My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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Student Review #2
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Followed here and elsewhere by over 1900 test-takers.
I have worked with students based in the US, Australia, Taiwan, China, Tajikistan, Kuwait, Saudi Arabia -- a long list of countries.
My students have been admitted to HBS, CBS, Tuck, Yale, Stern, Fuqua -- a long list of top programs.
As a tutor, I don't simply teach you how I would approach problems.
I unlock the best way for YOU to solve problems.
For more information, please email me (Mitch Hunt) at [email protected].
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