tolong dong jwb dengan benar dan tolong isi caranya dan tolong jelaskan dengan singkat

12.
Keliling ⅛ Lingkaran :
K = ⅛ × π × d
K = ⅛ × 22/7 × 35
K = ⅛ × 22 × 5
K = ¼ × 11 × 5
K = ¼ × 55
K = 13,75 cm

Jawaban : b. 13,75 cm

13.
Volume Tabung :
V = π × r × r × t
V = 22/7 × 14 × 14 × 25
V = 22 × 2 × 350
V = 44 × 350
V = 15.400 cm³

14.
Volume ¼ Tabung :
V = ¼ × π × r × r × t
V = ¼ × 22/7 × 14 × 14 × 25
V = 22/7 × 7 × 7 × 25
V = 22 × 175
V = 3.850 cm³

15.
Panjang Jari - Jari :
K = 1/5 × 2 × π × r
6,28 × 5 = 2 × 3,14r
31,4 = 6,28r
r = 31,4 ÷ 6,28
r = 5
Jari - Jari = 5 cm

Volume Kerucut :
V = ⅓ × π × r × r × t
V = ⅓ × 3,14 × 5 × 5 × 15
V = 15,7 × 5 × 5
V = 15,7 × 25
V = 392,5 cm³

Maaf Kalau Salah