diket: perbandingan panjang,lebar,tinggi= 5:3:2 jika volume balok 1.920 cm3 hitunglah a.panjang,lebar,tinggi b.luas permukaan balok

p = 5x
l = 3x
t = 2x

V = p x l x t
1920 = 5x . 3x . 2x
1920 = 30x
x = 64

p = 320
l = 192
t = 128

Lp = 2pl x 2pt x 2lt
= 2 x 320 x 192 + 2 x 320 x 128 + 2 x 192 x 128
= 253 952 cm^2

a.p:l:t = 5:3:2
volume = 1920
5x.3x.2x = 1920
30x^3 = 1920
x^3 = 1920/30
x^3 = 64
x = 4
p = 5x = 5.4 = 20 cm
l = 3x = 3.4 = 12 cm
t = 2x = 2.4 = 8 cm

b.luas permukaan :
(p.l)+(l.t)+(t.p)
=(20.12)+(12.8)+(8.20)
=240 + 96 + 160
= 496 cm^2