Ada yg bisa jawab no 18 & no 19 ?

luas = 4 . phi . r . r
2464 = 4 . 22/7. r. r
2464/4 = 22/7 . r . r
616 = 22/7 . r . r
616x 7 = 22 . r .r
4312 = 22 . r . r
4312/22 = r . r
196 = r^2
r = 14


volume = 4/3 . phi . r . r . r
= 4/3 . 22/7 . 14. 14 .14
= 4/3 . 22 . 2 . 14 . 14
= 34.496/3
= 11.498,6 cm^3


2. v = 4/3 . phi . r .r .r
904,752 = 4/3 . 3,14 . r . r . r
904,752 x 3 = 4 . 3,14 . r . r. r
2714,256 = 12,56 . r . r . r
2714,256/12,56 = r^3
216,1 = r^3
r = 6 cm


luas bola = 4. phi .r .r
= 4. 3,14 . 6 .6
= 452,16 cm^2

18.
L = 4πr²
2464 = 4 22/7 r²
r² = 88/7 : 2464
r² = 7/88 x 2464
r² = 196
r = 14

V = 4/3πr³
V = 4/3 22/7 14³
V = 4/3 22/7 2744
V = 11498,67