area of two circles are in ratio 16 :81 find ratio of their circumference
let radius of a circle be r1 and other be r2
so pi r12/pi r22=16/81
r1/r2=4/9
2 pi r 1/2 pi r 2=2r1/1r2=8/18=4/9
so pi r12/pi r22=16/81
r1/r2=4/9
2 pi r 1/2 pi r 2=2r1/1r2=8/18=4/9