Jawabanmu

2014-03-20T20:59:51+07:00
K = 2.phi.r 131 = 2.3,14.r 131 = 6,28.r 131/6,28 = r 20,86 cm = r
2014-03-20T21:12:14+07:00
K = 2 × phi × r 131= 2×3,14×r=6,28.r 131/6.28= r 20,86 cm = m