Jawabanmu

2014-04-12T18:08:00+07:00
L = 6,16 cm2 = 61.600 cm2
π x r2 = 61.600
r2 = 61.600 : π = 61.600 :     
= 61.600 x
    
= 2.800 x 7
    
= 19.600

 r   =  = 140 cm
Diameter: d = 2r = 2 x 140 = 280 cm

2014-04-12T23:59:02+07:00
6.6=πr^2 6.6=3.14 x r^2 6.6/3.14=r^2 r=√(330/157) r=1.449 atau dibulatkan 1.45