Question

如图,在△ABC中,AB=AC,∠ABC=2∠A,BD垂直AD于D,求∠DBC的度数.

Answer 1

∵AB=AC

∴∠ABC=∠ACB

∵∠ABC=2∠A

∴∠ACB=2∠A

∴5∠A=180°

∴∠A=36°

∴∠ACB=72°

∵BD⊥AC

∴∠BDC=90°

∴∠DBC=90°－∠ACB=18°