分别过B、C作X轴的垂线交于E、F,过B作BG⊥CF交于G
则E(2,0),F(9,0),G(9,5)
S△ABE=1/2 *AE*BE=1/2 *2*5=5
S△BCG=1/2 *BG*CG=1/2 *7*5=17.5
S△CFD=1/2 *FD*CF=1/2 *3*9=13.5
S四边形BEFG=EF*BE=7*5=35
S四边形ABCD=S△ABE+S△BCG+S△CFD+S四边形BEFG
=5+17.5+13.5+35=71
分别过B、C作X轴的垂线交于E、F,过B作BG⊥CF交于G
则E(2,0),F(9,0),G(9,5)
S△ABE=1/2 *AE*BE=1/2 *2*5=5
S△BCG=1/2 *BG*CG=1/2 *7*5=17.5
S△CFD=1/2 *FD*CF=1/2 *3*9=13.5
S四边形BEFG=EF*BE=7*5=35
S四边形ABCD=S△ABE+S△BCG+S△CFD+S四边形BEFG
=5+17.5+13.5+35=71