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标题: [求助]求三角形最大角的疑惑,是DS的题 [打印本页]

作者: joanjoans    时间: 2009-2-5 07:19     标题: [求助]求三角形最大角的疑惑,是DS的题

In ΔPQR, if PQ = x + 2, and PR = y, which of the three angles of ΔPRQ has the greatest
degree measure?
(1) y = x + 3
(2) x = 2

解释:
In any triangle, the largest angle is opposite the longest side. To determine the longest side it
suffices to determine whether y > x + 2. Since x + 3 > x + 2, it follows from (1) that y > x + 2.
Statement (1) alone is therefore sufficient. From (2) it follows that PQ = 2 and QR = 4. Thus, y can
be any value between 2 and 6; it follows that y > x, but it cannot be concluded that y > x + 2.
Statement (2) alone is therefore not sufficient. Therefore, statement (1) ALONE is sufficient, but
statement (2) alone is not sufficient to answer the question.

题目的答案是A. 可是从STATEMENT (1)中,只可以知道Y>X, 怎么知道Y就是最大边呢?三角形一共有3边,不是还有最后一边未知吗,为什么题目却说STATEMENT 1 是 SUFFICIENT?


作者: szgmater    时间: 2009-2-5 21:15

一直觉得题目有点怪异,因为觉得这道做过,在OG11里,280页32题,你去看看吧,你发的是不是漏了一些信息啊???


作者: joanjoans    时间: 2009-2-6 07:04

我是在网上DOWNLOAD OG10做的,不明白他说的解释,不知道是不是题目有遗漏啊,是在网上下的。晕死了,唉
作者: berylgirls    时间: 2009-2-8 13:29

题目有漏洞!!
作者: 菲菲    时间: 2009-2-10 12:52

pq=x,qr=x+2,pr=y,别的一样,就少了个条件




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