Question

如图所示,AD为∠CAE平分线,∠B＝40°,∠DAE＝80°,那么∠ACD＝? 写出步骤

Answer 1

∵AD平分∠CAE,∠DAE＝80

∴∠CAE＝2∠DAE＝160

∵∠B+∠ACB＝∠CAE,∠B＝40

∴40+∠ACB＝160

∴∠ACB＝120

∴∠ACD＝180-∠ACB＝180-120＝60