Question

如图,已知∠BOC=60°,OE平分∠AOC,OF平分∠BOC.

Answer 1

(1)若AO⊥BO,则∠EOF是都少度?

由于AO⊥BO

所以∠AOB=90°

由于OE平分∠AOC

所以∠EOC=（90+60）÷2=75°

由于OF平分∠BOC

所以∠FOC=30°

∠EOF=75-30=45°

（2）若∠AOC+∠EOF=210°,则∠EOF是都少度?

∠AOC+∠EOF=210°

2∠EOC+∠EOF=210°

2∠EOF+2×30°+∠EOF=210°

3∠EOF=150°

∠EOF=50°