Jawabanmu

2014-05-09T17:14:45+07:00
40/360 x Kel. lingkaran = 12.56
1/9 x kel. lingkaran = 12.56
kel lingkaran = 12.56 x 9 = 113.04

Kel. Lingkaran =  \pi x d
113.04 = 3.14 x d
113.04/3.14 = d
36 = d

Diameter = 36 cm