jika perbandingan balok 5:3:2 jika Volume Balok 810 cm maka luas permukaan adalah

V = px.lx.tx
810 = 5x.3x.2x
810 = 30x³
x³ = 810/30
x³ = 27
x = 3 cm

px = 5.3
= 15 cm

lx = 3.3
= 9 cm

tx = 2.3
= 6 cm

La = p x l
La = 15 x 9
La = 135 cm²

Ka = 2(p + l)
Ka = 2(15 + 9)
Ka = 2.24
Ka = 48 cm

Lp = (2.La) + (Ka.t)
Lp = (2.135) + (48.6)
Lp = 270 + 288
Lp = 558 cm²

maaf klw salah, semoga membantu :)