Question

如图12,AOB是直线,OE平分∠AOC,OF平分∠BOD,∠COD=30°,试求∠EOF的度数

Answer 1

∠AOC+∠BOD=180°-∠COD=150°

∠AOC=2∠AOC+∠BOD ∠BOD=2∠FOD

∠AOC+∠BOD=2(∠EOC+∠FOD)=150°

∠EOC+∠FOD=75°

∠EOF=∠EOC+∠COD+∠FOD=75+30=105°