Jawabanmu

2014-01-06T17:38:07+07:00
314 = 3.14 r2
r2   = 314/3.14
r2   = 100
r     =   \sqrt{100}
      = 10

so.. keliling rumusnya 2 \pi r
       2 x 3.14 x 10
       = 62,8

2014-01-06T18:15:59+07:00
L =  \pi r^{2}
314 =  \frac{22}{7}  r^{2}
 r^{2} = 314 x  \frac{7}{22}
 r^{2} = 100
r= \sqrt{100}
r=10

keliling=2 \pi r
=2 x 3.14 x 10
62.8 cm