Question

Perbandingan panjang, lebar, & tinggi sebuah balok adalah 4 : 3 : 2. Jika luas permukaannya 468 cm², hitunglah ukuran balok tersebut. Please gan, tolong kerjain. ampe kepikiran kalo tidur, hehehe

Answer 1

Lp = 2 (pl + pt + tl)

468 = 2 (4x.3x + 4x.2x + 3x.2x)

468÷2 = 12x² + 8x² + 6x²

234 = 26x²

234÷26 = x²

9 = x²

√9 = x

3 = x

P = 4x = 4 x 3 = 12 cm

L = 3x = 3 x 3 = 9 cm

T = 2x = 2 x 3 = 6 cm

Jadi ukuran balok tsb adalah 12 x 9 x 6

× Mohon maaf bila ada kesalahan. Semoga membantu^^ ×

Answer 2

P : l : t = 4 : 3 : 2
p : l = 4 : 3
3p = 4l
p = 4/3 l

l : t = 3 : 2
3t = 2l
t = 2/3 l

2 (p x l) + 2 (p x t) + 2 (l x t) = 468
2(pl + pt + lt) = 468
2(4/3 l x l) + 2(4/3 l.t + 2lt = 468
8/3 l² + 8/3 lt + 2lt = 468
8/3 l² + 14/3 lt = 468
8/3 l² + 14/3 (2/3 l x l) = 468
8/3 l² + 28/9 l² = 468
24/9 l² + 28/9 l² = 468
52/9 l² = 468
52l² = 468 x 9
52l² = 4212
l² = 4212 : 52
l² = 81
l =√81 = 9


p : l : t = 4 : 3 : 2

p : l = 4 : 3
3p = 4l
3p = 4 (9)
3p = 36
p = 36 : 3 = 12

l : t = 3 : 2
3t = 2l
3t = 2 (9)
3t = 18
t = 18 : 3 = 6

Jadi panjang balok = 12 cm
lebar balok = 9 cm
tinggi balok = 6 cm

Maka Ukuran balok = 12 cm x 9 cm x 6 cm