Question

如图,在3角形abc中,角acb为100度ac等于ae,bc等于bd角dce等于

Answer 1

∵AC=AE,BC=BD

∴∠ACE=∠AEC,∠BCD=∠CBD

∴∠ACE+∠BCD=∠AEC+∠CBD=180°-∠DCE,

∠ACE+∠BCD=∠ACB+∠DCE=100°+∠DCE,

∴180°-∠DCE=100°+∠DCE,

解得∠DCE=40°.

选D.