[問題]GWD27-27

[kaijen]

Q27:
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


答案給A 我覺得應該是D吧

[dibert8]

A = PI * (R^2 - r^2)
(1) r = BC + CD = 3, R = AB + BC = r + BC = 3 + 2 = 5
(2) R = CD + DE = 5, r = AD/2 = (5 + 1)/2 = 3
=> (D)