If circles x and y have the same area and circle x has a circumference of 18π, half of the radius of circle y is:	Choose the correct choice
A) 16 B) 4.5 C) 4 D) 2 E) 1

Rationale: "x be radius of circle x y be radius of circle y given : pi * x ^ 2 = pi * y ^ 2 also , 2 * pi * x = 18 * pi x = 9 thus y = 9 y / 2 = 4.5 ans : b"
Answer: B