△AEF≌△BEF
则:∠AEF=∠BEF
ED平分∠AEC
则:∠AED=∠CED
而BEC为一直线
则:(∠AEF+∠BEF) +(∠AED+∠CED)=180
则:∠FED=∠AEF+∠AED=1/2*(180)=90
画画图,仔细算算,就不难了.
好好学习,快乐成长.
△AEF≌△BEF
则:∠AEF=∠BEF
ED平分∠AEC
则:∠AED=∠CED
而BEC为一直线
则:(∠AEF+∠BEF) +(∠AED+∠CED)=180
则:∠FED=∠AEF+∠AED=1/2*(180)=90
画画图,仔细算算,就不难了.
好好学习,快乐成长.