SOS~~GWDMATH13-13答案没错吗？help~

Sophia0703

Q13:？？？？？？？？？？？？？？？？？？？？？？？？？？？？？

Is the measure of one of the interior angles of quadrilateral ABCD equal to 60 degrees?

(1)     Two of the interior angles of ABCD are right angles.

(2)     The degree measure of angle ABC is twice the degree measure of angle BCD.

                  

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

请问下为什么A不可以呢？四边形知道两个角都是90，那不就是矩形吗？这样不就可以回答问题NO吗？

thanks~

PS:ans：E

[此贴子已经被作者于2008-12-25 13:46:20编辑过]

Sophia0703

呜呜~~~没人理我啊~

xiaoy791

1单独不行，四边形知道两个角都是90，那不就是矩形吗？这样不就可以回答问题NO吗？try think about 一个矩形和一个直角三角形的组合，这儿就不画图了，其他两个角加起来是180就可以了，随意组合；

2和1一起也不行，还是上面那个图，如果angle ABC是90，angle BCD是45，那么就没有等于60的角了

这种题很容易忽视

Sophia0703

啊~~~我怎么忽视啦这个，LS说的是直角的梯形吧~~~~

太粗心啦，哎...

thanks~