2 buah bola masing masing dengan perbandingan volume 27:8 tentukan 1. Perbandingan masing masing jari jari 2. Luas permukaan bola

Bab Bangun Ruang
Matematika SMP Kelas VIII

bola
1] v1 : v2 = 27 : 8
(r1)^3 : (r1)^3 = 27 : 8
r1 : r2 = 27^(1/3) : 8^(1/3)
r1 : r2 = 3 : 2

2] L1 : L2 = (r1)² : (r2)²
L1 : L2 = 3² : 2²
L1 : L2 = 9 : 4

[tex] \frac{4/3 * \pi * r1^3 }{4/3 * \pi * r2^3} = \frac{27}{8} [/tex]
[tex]\frac{r1^3}{r2^3} = \frac{27}{8}[tex]
r1 = ∛27 = 3 cm
r2 = ∛8 = 2 cm

1) perbandingan masing masing jari jari = r1/r2 = 3/2
2) Lp bola
     a) Lingkaran 1 = 4 x π x r² = 4 x 3,14 x 3^2 = 12.56 x 9 = 113.04 cm^2
     b) lingkaran 2 = 4 x π x r² = 4 x 3.14 x 2^2 = 12.56 x 4 = 50.24 cm^2