Jawabanmu

2014-01-14T19:24:18+07:00
K  = 2p + 2l
40 = 2x + 2 (x + 4)
40 = 2x + 2x + 8
40 = 4x + 8
40 - 8 = 4x
32 = 4x
x = 32/4
x = 8 
l = 8 cm
P = 8 + 4
   = 12 cm
L = pl
L = 8 . 12
L = 96 cm²

gtw
jwbnnya bner
iya makasih yaa semuanya :)
sma-sama :)
u're well :)