Jawabanmu

2014-05-01T13:01:26+07:00
Panjang diagonal 3√2 = sisinya 3 
Luas SEluruh permukaan = 6 x 3 X 3  = 54 CM²
2014-05-01T13:04:16+07:00
Panjang diagonal sisi = 3 akar 2

s^2 + s^2 = (3 akar 2)^2
2 s^2 = 9 x 2
2 S^2 = 18
s^2 = 9
s = 3

luas permukaan kubus = 6 x s x s
= 6 x 3 x 3 = 54