如图四边形ABCD中EF∥AD,MN∥AB,MN与EF交于点P且点P在BD上,图中面积相等的四边形有_对.

问题描述:

如图四边形ABCD中EF∥AD,MN∥AB,MN与EF交于点P且点P在BD上,图中面积相等的四边形有______对.

∵在平行四边形ABCD中,BD是对角线,EF∥BC,GN∥AB,
∴S△ABD=S△DBC,S△BEP=S△BNP,S△MPD=S△DPF
∴S△ABD-S△BEP-S△MPD=S△DBC-S△BNP-S△DPF
∴S▱AEPM=S▱PNCF
∴S▱AEPM+S▱EBHP=S▱PNCF+S▱EBNP
即,S▱ABMN=S▱EBCF
同理,S▱AEFD=S▱CDMN
S四边形ABPM=S四边形CBPF;S四边形ADPE=S四边形CDPN
∴图中有5对四边形面积相等,即:S▱AEPM=S▱PNCF,S▱ABNM=S▱EBCF,S▱AEFD=S▱CDMN,S四边形ABPM=S四边形CBPF;S四边形ADPE=S四边形CDPN
故答案是:5.