The ratio of the radius of two circles is 1: 9, and then the ratio of their areas is? Choose the correct choice from the following answers:  A) 1: 8  B) 1: 6  C) 1: 9  D) 1: 3  E) 1: 81
r1: r2 = 1: 9   Πr12: Πr22   r12: r22 = 1: 81   Answer:1: 81
<result>E</result>
The ratio of the radius of two circles is 1: 9, and then the ratio of their areas is?