Jawabanmu

2014-06-06T18:44:29+07:00
Keliling = 2 phi r
12 = 2 x 3,14 x r
12 = 6,28 r
1,9 = r
2014-06-06T19:16:50+07:00
Keliling = 2 phi r
12 = 2 * 3,14 * r
12 = 6,28 r
r = 12 : 6,28
r = 1,9 cm