Jawabanmu

2014-06-10T21:13:47+07:00
180 = 5x .4 + 3x.4 + x.4
180 = 20x + 12x + 4x
180 = 36x
5 = x

5.5 = 25
3.5 = 15
1.5 = 5

luas permukaan = 2.25.15 + 2.25.5 + 2.15.5
= 750 + 250 + 150
= 1150 cm2
1 4 1
2014-06-10T21:37:23+07:00
Panjang seluruh rusuk balok = 4 (p+l+t)
180 = 4 (5p+3l+1t)
180 = 20p +12l + 4t
180 = 36plt
plt = 180 : 36
plt = 5

p = 5 x 5 = 25
l = 3 x 5 = 15
t = 1 x 5 = 5

l.p.b = 2 ((p x l ) + (l x t) + (t x p))
l.p.b = 2 ( 25 x 15 + 15 x 5 + 5 x 25 )
l.p.b = 2 ( 575)
lpb = 1.150 cm

maaf kalau salah
1 4 1