Question

BF、BE分别是∠ABC与∠ABD的平分线,AE⊥BE于E,AF⊥BF于F.试说明四边形AEBF是矩形

Answer 1

C B D在一条直线上?

BF、BE分别是∠ABC与∠ABD的平分线

又因为 ∠ABC+∠ABD=180

∠ABF=1/2∠ABC

∠ABE=1/2∠ABD

∠EBF=∠ABF+∠ABE=1/2(∠ABC+∠ABD)=90

AE⊥BE于E,AF⊥BF于F

则 ∠AEB=AFB=90

四边形AEBF为矩形