Question

Diketahui sebuah balok memiliki perbandingan p:l:t = 4:2:3.
Jika luas permukaan balok 1.300 cm2. Hitunglah ukuran panjang, lebar dan tinggi balok tersebut?? Please pake jalan

Answer 1

Misal :
p = 4x
l = 2x
t = 3x

Lp = 2 (pl + pt + lt)
1300 = 2 (8x² + 12x² + 6x²)
1300 : 2 = 26x²
650 = 26x²
650 : 26 = x²
25 = x²
√25 = x
5 = x

Maka :
p = 4x = 4 x 5 = 20 cm
l = 2x = 2 x 5 = 10 cm
t = 3x = 3 x 5 = 15 cm

Answer 2

Luas permukaan = 2 ( pl + pt + lt )
misal p = 4a, l = 2a, t = 3a, maka

1300 = 2 (( 4a x 2a) + (4a x 3a) + (2a x 3a))
1300 = 2 ( 8a^2 + 12a^2 + 6a^2 )
1300 = 52a^2
a^2 = 25
a = 5 cm

p = 4 x 5 = 20 cm
l = 2 x 5 = 10 cm
t = 3 x 5 = 15 cm