perbandingan tiga rusuk suatu balok adalah 3 : 2 :1 jika volume balok 162 liter ,maka luas permukaaan balok tersebut adalah

p : l : t = 3x : 2x : x
V = 162 liter = 162 dm^3

V = p . l . t
162 = 3x . 2x . x
162 = 6x^3
x^3 = 27
x = 3

p = 3.3 = 9 dm
l = 2.3 = 6 dm
t = 3 dm

Lp = 2 (pl + pt + lt)
Lp = 2 (9.6 + 9.3 + 6.3)
Lp = 2 ( 54 + 27 + 18)
Lp = 2 . 99 = 198 dm^2

162=3x × 2x × 1x
162=6x³
162/6=x³
³√27=x
3=x
maka..
3(3)=9
2(3)=6
1(3)=3

luas permukaan balok:
2(9×6+9×3+3×6)
=2(99)
=198dm²