合聚咖

合聚咖

(2007

admin

AB∥CF.证明如下:

∵∠AED与∠CEF是对顶角,

∴∠AED=∠CEF,

在△ADE和△CFE中,

∵DE=FE,∠AED=∠CEF,AE=CE,

∴△ADE≌△CFE.

∴∠A=∠FCE.

∴AB∥CF.