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? | 
