Question

三角形的东西不会,求帮帮忙.

Answer 1

在△ABC中,∠BAC+∠ABC+∠ACB=180°,

∠ABC+∠ACB=180°-∠a,

1/2(∠ABC+∠ACB)=(180°-∠a)/2=90°-1/2∠a

在△BOC中,CF、BE分别为∠ACB、∠ABC的平分线,

∠BOC=180°-1/2(∠ABC+∠ACB)=180°-(90°-1/2∠a)=90°+1/2∠a