The ratio of the radius of two circles is 1: 3, and then the ratio of their areas is?  Choose the correct choice from the following answers
A) 1:6  B) 1:0  C) 1:9  D) 1:2  E) 1:1
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?