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Measure of external angle.

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Source: — Data Sufficiency |
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by DanaJ » Thu Jan 29, 2009 8:12 am
1. is sufficient because the external angle corresponding to the angle with a measure of 72 degrees is (180 - 72) = 108.
2. is insufficient because just knowing that the triangle is isosceles is not enough. We would need a numeric value for one of its angles to answer the question.

So I'd go with A.
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by sanjay_dce » Thu Jan 29, 2009 8:20 am
IMHO E is the ans Danaj has mistakenly assumed which exterior angle is being asked, its not necesarrily connected with the interior angle given in stmt2.

hence E
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by DanaJ » Thu Jan 29, 2009 8:35 am
I suppose you're right.... I don't really know... I guess my explanation would be ok if we had been asked the measure of any of the exterior angles... Not a particular angle. It's all about wording.
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by Stuart@KaplanGMAT » Thu Jan 29, 2009 12:41 pm
DanaJ wrote:I suppose you're right.... I don't really know... I guess my explanation would be ok if we had been asked the measure of any of the exterior angles... Not a particular angle. It's all about wording.
I agree.

The question asks ""What is the measure of an external angle of
the triangle ABC?"

From statement (1), we can certainly determine the meansure of AN external angle of the triangle. Therefore, (1) is sufficient on its own.

"Is this what the question writer intended to ask" is a completely different issue and speaks to the reliability of the source. Whenever one posts a question, one should post the source as well so we know how seriously to take it.
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by sanjay_dce » Fri Jan 30, 2009 10:56 pm
DanaJ wrote:I suppose you're right.... I don't really know... I guess my explanation would be ok if we had been asked the measure of any of the exterior angles... Not a particular angle. It's all about wording.[/quote

Looks like the question is incomplete, otherwise (with the information provided out here)DanaJ u r correct, I take my words back :oops:
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