Question

如图角AOB=120度,角COD=20度,OE平分角AOC,OF平分角BOD,求角EOF度数?

Answer 1

∵∠AOB=120°,∠COD=20°

∴∠AOC+∠BOD=∠AOB-∠COD=120°-20°=100°

又∵OE平分∠AOC,OF平分∠BOD

∴∠EOC+∠DOF= 12∠AOC+ 12∠BOD= 12（AOC+∠BOD）= 12×100°=50°

∴∠EOF=∠EOC+∠DOF+∠COD=50°+20°=70°