hitunglah harga bandul emas tersebut

r = 21 mm = 2,1 cm
t = 10 mm = 1 cm
Volume = volume 1/2 bola + volume kerucut
= 1/2 . 4/3 πr^3 + 1/3 πr^2 t
= 2/3 πr^3 + 1/3 πr^2 t
= 1/3 πr^2 (2r + t)
= 1/3 . 22/7 . 2,1 . 2,1 (2 . 2,1 + 1)
= 22/21 . 4,41 (4,2 + 1)
= 22 . 0,21 (5,2)
= 24,024 cm^2
Berat = 24,024 x 8 gram = 192,192 gram
Harga = 192,192 x Rp80.000,-
= Rp15.375.360,-

Mapel : Matematika
Kelas : IX SMP
Bab : Bangun Ruang

Pembahasan :
Volume Bandul = V 1/2 Bola + V Kerucut
V Bandul = (2/3 pi r³) + (1/3 pi r²t)
V Bandul = (2/3 . 22/7 . 21³) + (1/3 . 22/7 . 21² . 10)
V Bandul = 19404 + 4620
V Bandul = 24.024 mm³
V Bandul = 24,024 cm³

Harga = (V Bandul x 8) x Rp80.000
Harga = (24,024 x 8) x Rp80.000
Harga = 192,192 x Rp80.000
Harga = Rp15.375.360