第2个回答 2013-05-04
S△ABH-S△FGH=10
1/2AB×AH-1/2GF×GH=10
1/2AB×(AG-GH)-1/2GF×GH=10
1/2AB×AG-1/2GH×(AB+GF)=10
1/2×12×5-1/2GH×(AB+GF)=10
GH×(AB+GF)=40
GH×(12+GF)=40……(1)
∵AB∥GF
∴△ABH∽△FGH
∴AB/GF=AH/GH=(AG-GH)/GH
即12/GF=(5-GH)/GH
GH×(12+GF)=5GF……(2)
5GF=40
GF=8
∴AD=AG+DG=AG+GF=5+8=13
∴S长方形ABCD=12×13=156