OG math 求三角形最大角11题是不是答案有问题?
11. 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
Explanation:
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.
感觉(1)也只是判断了2边呀,第三边又不知道大小,怎么能确定最大角呢? |