Jawabanmu

2014-06-09T17:57:42+07:00
5a x 4a x 2a =1080
40a^3=1080
a^3=27
a=3
lalu subtitusi ke panjang dan lebar
5a x 4a =
= 5(3) x 4(3)
=15 x 12 = 180
2014-06-09T17:58:16+07:00
V = plt
1080 = 5x × 4x × 2x
1080 = 40x³
1080 : 40 = x³
    27       = x³
   ∛27     = x
    x        = 3

p = 5 x 3 = 15 cm
l  = 4 x 3 = 12 cm
t  = 2 x 3 = 6 cm

p x l = 15 x 12
       = 180 cm