pake cara krrjany juga ya

Volume kubus = Volume balok = 1.000 cm³
sisi kubus = ∛1000 = 10 cm 
p balok = 2s = 2 x 10 cm = 20 cm
t balok = 1/ 2 lebar balok ⇒ t = 1/2 l 

Volume balok = p x l x t 
1.000 = 20 x l x 1/2 l
1.000 = 10 l²
l² = 100
l = √100 = 10 cm 
t = 1/2 l ⇒ t = 1/2 x 10 = 5 cm 
berarti ukuran balok , p = 20 , l = 10 , dan t = 5 
Luas permukaan balok = 2 { (pxl)+(pxt)+(lxt)}
= 2 {(20x10)+(20x5)+(10x5)}
= 2 ( 200 + 100 + 50 )
= 2 ( 350 )
= 700 cm²
semoga membantu