扫描二维码，直接登录
题库 / GMATLA-DS-18
In the figure, points A, B, C, D, and E lie on a line. A is on both circles, B is the center of the smaller circle, C is the center of the larger circle, D is on the smaller circle, and E is on the larger circle. What is the area of the region inside the larger circle and outside the smaller circle?
(1) AB = 3 and BC =2
(2) CD =1 and DE = 4
Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.
Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.
BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.
EACH statement ALONE is sufficient.
Statements (1) and (2) TOGETHER are NOT sufficient.
还没有题目讲解（毕出老师会陆续发布对官方考题的解读，请保持关注）。
AD=AC+CD=CE+CD=6 小圆半径r=3 大圆半径R=5 可求
我大概是傻了
(2) ce=5, ca=5, so ad= ca+cd=6, so ab=3
(2) CD = 1 and DE = 4 --> CD+DE=CE=R=5CD+DE=CE=R=5. Next, AD+DE=AE=DIAMETER=2R=10AD+DE=AE=DIAMETER=2R=10, and since AD=2rAD=2r, then 2r+DE=102r+DE=10 --> 2r+4=102r+4=10 --> r=3r=3. Sufficient.
注意第二问是可以求的，知道R之后，2R-DE整体除以2可以求r
仔细点呀！！！！
注意第二问是可以求的，知道R之后，2R-DE整体除以2可以求r