Jawabanmu

2014-01-14T22:43:41+07:00
42=2 x 22/7 xr
42 x 2 x 22/7=r
1,83=r

luas=pi x r kuadrat
l=3,14 x 1,83 x 1,83
l=10,515546cm
2014-01-14T23:12:23+07:00
2 phi r = 42
phi r = 21
22/7 x r = 21
r = (21x7)/22 kira-kira 6,68

L= phi x r x r = 21 x 6,68 = 140 cm kuadrat