Question

如图,在三角形ABC中角BAC＝5角ABC,角C＝2角ABC,BD垂直AC,交CA的延长线于点D,求证角CBD＝45

Answer 1

∵∠BAC=5∠ABC,∠C=2∠ABC

∴8∠ABC=180

∴∠ABC=22.5

∴∠BAC=112.5

∴∠DAB=67.5

∴∠DBA=22.5

∴∠CBD=45