点D在三角形ABC的AC边上,E在CB延长线上,且AD=BE,求EF*BC=AC*FD

做DG//EC交AB于点G.
DG:BE=DF: EF
DG:BC=AD:AC AD=BE
DG:BE=BC:AC
DF:EF=BC:AC
EF*BC=DF*AC