BD:BC=2:3
AB=AC,∠BAC=108°
∠ABC=∠ACB=36°
BD=AB
∠BAD=∠BDA=72°
∠DAC=108° -72° =36° =1/3倍,∠BAC
所以D点是等腰△ABC 边 BC上的三等分点
所以
BD:BC=2:3
BD:BC=2:3
AB=AC,∠BAC=108°
∠ABC=∠ACB=36°
BD=AB
∠BAD=∠BDA=72°
∠DAC=108° -72° =36° =1/3倍,∠BAC
所以D点是等腰△ABC 边 BC上的三等分点
所以
BD:BC=2:3