tolong ya teman di jawab

15. V = ⅓. phi. r². t
= ⅓. 3,14. 5. 5. 6
= 3,14. 5. 5. 2
= 157 dm³ (a)
17. V = phi. r². t
3.850 = 22/7. 7. 7. t
3.850 = 154. t
t = 3.850 : 154
t = 25 cm (c)
19. V = ⅓. phi. r². t
= ⅓. 22/7. 10,5. 10,5. 30
= 22. 1,5. 10,5. 10
= 3.465 cm³ (d)