Jawabanmu

2014-08-31T14:57:35+07:00
AB = 50
CD = EF = 20
AE adalah AB-EF= 50-20= 30/2= 15cm
2014-08-31T15:13:28+07:00
AB = 50      
CD =20
AE = FB
DC = EF
AE = ?
AE = AB - EF : 2
      = 50 - 20 : 2
      = 30 : 2
      = 15