tolong jwab!! pakai cara secepat mungkin

18) V bola
= ½ × 4/3 × π × r³
= ½ × 4/3 × 22/7 × 9 × 9 × 9
= 1527,43 cm³
V bola = V tabung
V tabung = π × r² × t
1527,43 = 3,14 × 6 × 6 × t
1527,43 = 113,04 × t
t = 1527,43 ÷ 113,04
t = 13,5 cm ( D )

19) d = 4 m
r = 2 m
Lp ½ bola
= ½ × 4 × π × r²
= ½ × 4 × 3,14 × 2 × 2
= 25,12 m²
Luas 15 parasut
= 15 × 25,12 m²
= 376,8 m² ( B )