Jawabanmu

2014-06-09T18:19:00+07:00
R= 10 cm

keliling = phi.d
=62.8/3.14
=20 cm
r = 10 cm
2014-06-09T18:19:35+07:00
K = π × d
62,8 = 3,14 × d
62,8 : 3,14 = d
       d        = 20 cm

r = 1/2 d
r = 1/2 × 20 = 10 cm