Jawabanmu

2014-05-29T13:23:24+07:00
V = P*L*T
810 = 5x*3x*2x
810 = 30x^3
810/30 = x^3
27 = x^3
x = 3

maka,
p = 15cm
l = 9cm
t = 6cm

jadi,
lp = 2 (pl+pt+lt)
    = 2 (15*9 + 15*6 + 9*6)
    = 2 (135+90+54)
    = 2 (279)
     = 558 cm2