The ratio of the radius of two circles is 1: 3, and then the ratio of their areas is?
Choose the correct option
A) 1:8
B) 1:6
C) 1:9
D) 1:3
E) 1:4
r1: r2 = 1: 3   Πr12: Πr22   r12: r22 = 1:9   Answer: 1:9
<result>C</result>
The ratio of the radius of two circles is 1: 3, and then the ratio of their areas is?