Question

初二几何题、

如图，∠A=60°，BD，CE是两条高。请说出DE=1/2BC的理由、

Answer 1

∠A=60°
∠ACE=30°
AE=1/2AC
同理AD=1/2AB
AE :AC =1:2
AD :AB =1:2
AE :AC=AD :AB
∠A=∠A
△AED∽△ABC
AE：AC=DE :BC =!:2
DE=1/2BC