Jawabanmu

2014-04-13T20:20:27+07:00
P = 3/(3+2) x (80/2)            L = 40 - 24 = 16 cm
   = 3/5 x 40
   = 24 cm 

A = P x L
   = 24 x 16 
   = 384 cm²
2 3 2
2014-04-13T20:22:29+07:00
misal
p = 3a
l = 2a 

Keliling persegi panjang = 2(p+l)
80 = 2 (3a+2a)
80 = 2(5a)
80 = 10a
a = 80 : 10
a = 8

Jadi panjang = 3 x 8 = 24 cm
lebar = 2 x 8 = 16 cm
Jadi selisih panjang dan lebar = 24 - 16 = 8 cm

P = 3/(3+2) x (80/2)            L = 40 - 24 = 16 cm
   = 3/5 x 40
   = 24 cm 

A = P x L
   = 24 x 16 
   = 384 cm²

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