The ratio of the radius of two circles is 1: 3, and then the ratio of their areas is?	Choices:	A) 1: 5	B) 1: 8	C) 1: 9	D) 1: 1	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?