Jawabanmu

2014-01-14T19:27:48+07:00
Diameternya 20
keliling 2.π.r = 20π = 62.8
luas π r² = π.10² = 314
2014-01-14T19:32:32+07:00
Diameter: 2x10 = 20
keliling: \pi d = 3,14 x 20
                   = 62,8
luas:  \pi  r^2 = 3,14 x 10 x10
                               = 3,14..