Question

Panjang lebar, dan tinggi balok berbanding 5 : 4 : 3. jika jumlah panjang rusuk balok 144 cm, tentukan:
a. panjang, lebar dan tinggi balok
b. volume balok
c. luas permukaan balok

Answer 1

Misal :
p = 5n
l = 4n
t = 3n

jumlah p.rusuk = 4.(p+l+t)
144 = 4.(5n+4n+3n)
144:4 = 12n
36 = 12n
n = 36/12
n = 3

a) p = 5n = 5.3 = 15 cm
l = 4n = 4.3 = 12 cm
t = 3n = 3.3 = 9 cm

b) V balok = p.l.t
= 15.12.9
= 1620 cm kubik

c) Lp balok = 2.(pl+pt+lt)
= 2.(15.12 + 15.9 + 12.9)
= 2.(180 + 135 + 108)
= 2.423
= 846 cm²