bantu jawab no.11,16,17+cara ya. thanks

11. Lp bangun = 2x3,14x12x20 = 1.507,2 cm²

16. L.p.1/2 bola padat= 3 x phi x r^2
                          = 3 x 3,14 x 10^2= 942 cm2
17. Diameter bola = rusuk kubus
r = 1/2 d
V = 4/3 π r³ = 4/3 π 1/8. d³ = 1/6 π d³ = 1/6 (22/7)(21³) = 4.851