Jawabanmu

2014-06-12T08:32:40+07:00
P : l : t = 5 : 3 : 2
lebar 15 cm 
15 = 3x
x = 5
panjang = 5x = 5(5) = 25 cm
tinggi = 2x = 2(5) = 10 cm
jumlah seluruh panjang rusuk = 4p + 4l + 4t = 4(25) + 4(15) +4(10) = 100 + 60 + 40 = 200 cm
1 4 1