DF=FC,S1=S3,所以△ADF与△EFC分别以DF、FC为底时高相等,所以AE‖DC,
S△AEF=S△ADF+S△FCE=S1+S2
梯形分为5个S1
5*S1=3 S1=3/5
S△AEF=2*S1=6/5平方厘米