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Hi MathRevolution,

how did you get this "Since BE=2 and DB=4, degree B = degree C=60 degree."

Question has given BE=3 right?
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FlyingCycle
Hi MathRevolution,

how did you get this "Since BE=2 and DB=4, degree B = degree C=60 degree."

Question has given BE=3 right?


FlyingCycle,

You have a valid point, that is a typo. It is already given BE=3 hence it should have been BE=3 and DB=6.

In a 30 : 60 : 90 triangle sides are in the ratio \(x : x\sqrt3 : 2x\)
From the figure we see ED is perpendicular to BC hence angle DEB = 90

Now using the given information that two sides are in the ratio \(x\) and \(2x\) and one angle is 90 we can conclude it's a 30 60 90 \(\Delta\). Hence angle B ( and also angle C) is 60.

Hope it's clear.

Bunuel, MathRevolution, Sir please can you correct the typo, so as to prevent others too from getting confused. Thank you.
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Hi MathRevolution,

how did you get this "Since BE=2 and DB=4, degree B = degree C=60 degree."

Question has given BE=3 right?


FlyingCycle,

You have a valid point, that is a typo. It is already given BE=3 hence it should have been BE=3 and DB=6.

In a 30 : 60 : 90 triangle sides are in the ratio \(x : x\sqrt3 : 2x\)
From the figure we see ED is perpendicular to BC hence angle DEB = 90

Now using the given information that two sides are in the ratio \(x\) and \(2x\) and one angle is 90 we can conclude it's a 30 60 90 \(\Delta\). Hence angle B ( and also angle C) is 60.

Hope it's clear.

Bunuel, MathRevolution, Sir please can you correct the typo, so as to prevent others too from getting confused. Thank you.


In question its not mentioned its a right triangle.... just by seeing the picture can we say its a right angle and assume angle c is 60 degree?
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FlyingCycle
Hi MathRevolution,

how did you get this "Since BE=2 and DB=4, degree B = degree C=60 degree."

Question has given BE=3 right?


FlyingCycle,

You have a valid point, that is a typo. It is already given BE=3 hence it should have been BE=3 and DB=6.

In a 30 : 60 : 90 triangle sides are in the ratio \(x : x\sqrt3 : 2x\)
From the figure we see ED is perpendicular to BC hence angle DEB = 90

Now using the given information that two sides are in the ratio \(x\) and \(2x\) and one angle is 90 we can conclude it's a 30 60 90 \(\Delta\). Hence angle B ( and also angle C) is 60.

Hope it's clear.

Bunuel, MathRevolution, Sir please can you correct the typo, so as to prevent others too from getting confused. Thank you.


In question its not mentioned its a right triangle.... just by seeing the picture can we say its a right angle and assume angle c is 60 degree?

Someone mentioned similar doubt. I don't think question can be solved without such assumption.

Posted from my mobile device
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I don't think in GMAT we would get such ambiguity in the question. We cannot just assume whatever we want and get the answer :D

stne point is also right that without assumption we wouldn't get the answer :D
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