tolong jawab no 3,4,dan 6?

3) . Mencari r :
L. Alas = πr²
314 = 3, 14 × r²
314 : 3, 14 = r²
100 = r²
r² = √100
r. = 10cm
d= 2×r = 2×10 =20cm
- Luas selimut = 2πrt
= 2×3, 14×10×28
= 6, 28×10×28
= 62, 8×28
=1, 758.4 cm²
- Luas permukaan = 2πr. (r+t)
= 2×3, 14×10(10+28)
= 62, 8 × 38
= 2, 386.4cm²
4). Mencari r :
Luas selimut = 2πrt
1320 = 2 πr² × 20
1320 :20 = 2 πr²
66 = 2 πr²
r² = 66 × 2 ×π
r² = 132 × 22/7
r² = 132 × 7/22
r² = 924 : 7
r² = 42
r = √42 = 6.48 cm
d= 2×r= 2×6.48= 12, 96 cm

- L. Alas = πr²
=3, 14×6, 48×6, 48
=131, 850 cm ²





#kanggoin baru segitu dapet nya ya..... :)