Jawabanmu

2014-05-16T11:30:21+07:00
P = 2l - 3

kll = 2p + 2l
18 = 2 (2l - 3) + 2l
18 = 4l - 6 + 2l
18 + 6 = 6l
 24  = 6l
 l = 4 cm

p = 2l -3 
p = 2 (4) - 3
   = 8 - 3
p = 5 cm

L= p x l
  = 5 cm x 4 cm
  = 20  cm^{2}