来自冯怀真的问题
如图,△ABC中,AB=AC,与∠BAC相邻的外角为80°,则∠B=______度.
如图,△ABC中,AB=AC,与∠BAC相邻的外角为80°,则∠B=______度.
1回答
2020-03-17 12:31
如图,△ABC中,AB=AC,与∠BAC相邻的外角为80°,则∠B=______度.
如图,△ABC中,AB=AC,与∠BAC相邻的外角为80°,则∠B=______度.
∵∠DAC=80°
∴∠BAC=180°-∠DAC=180°-80°=100°
∵在△ABC中,AB=AC
∴∠ABC=∠ACB=180°−100°2