Question

如圖，平行四邊形ABCD中，E是AB的中點，G是AC上一點，，連EC延長交AD于F，求的值

Answer 1

_{延長CD與EF的延長線相交于點H}

_{∵HC∥AB,∴△HGC∽△EGA}

_{∴AG/CG=AE/HC=1/5}

_∵E是AB中點_{∴AE/AB=AE/DC=1/2}

_∴AE/DH=1/3

_{∵HC∥AB,∴△DFH∽△AFE}

_{∴DF/FA=DH/AE=3}