Question

∠AOB=120°,OE平分∠AOB,C为∠AOE内一点,∠BOC=2∠AOC,求∠EOC的度数.

Answer 1

∵OE平分∠AOB,∠AOB=120

∴∠BOE=∠AOE=∠AOB/2=120/2=60

∵∠AOC+∠BOC=∠AOB,∠BOC=2∠AOC

∴3∠AOC=120

∴∠AOC=40

∴∠EOC=∠AOE-∠AOC=60-40=20