Question

初三数学，求详解

Answer 1

AB∥ED，则晌橘OA/OB=OE/宴键团OD，所以OA*OD=OB*OE，
BC∥EF，则OC/OB=OE/OF，所以OC*OF=OB*OE，
于是亮灶OA*OD=OC*OF

Answer 2

∵ AB∥ED
∴ ∠OAB =∠OED ∠OBA =∠液旁郑ODE
△OAB ∽△ED
OA/OE = OB/OD------- ①
同理启贺
OC/OE = OB/OF------- ②闹颂
①比 ②
OA/OC = OF/OD
∴ OA*OD = OC*OF

Answer 3

因为AB//ED,所以三角形OAB与OED相似，所以OA/OB=OE/OD,变形得OA*OD=OB*OE
因唯芦漏为BC//EF，所哗手以三角形OCB与OEF相似，所以指烂OC/OB=OE/OF,变形得OC*OF=OB*OE
综上得OA*OD=OC*OF

Answer 4