panjang lebar tinggi sebuah balok berbanding sebagai 3:2:1 jika volume balok 750cm3 maka luas sisi balok adlh A. 275cm2 , B. 450cm2, C. 550 cm2, D. 900cm2 tolon

BALOK

misal

p:l:t = 3:2:1

p = 3x
l = 2x
t = x

V = 750
p×l×t = 750
(3x)(2x)(x) = 750
6x^3 = 750
x^3 = 750/6
x^3 = 125
x^3 = 5^3
x = 5 cm

p = 3x = 3×5 = 15 cm
l = 2x = 2×5 = 10 cm
t = x = 5 cm

Luas = 2×(pl + pt + lt)
=> 2×(15×10 + 15×5 + 10×5)
=> 2×(150 + 75 + 50)
=> 2×275
=> 550 cm^2