∵AB=AC,点D在AC上,且AD=DB=BC
∴∠ABC=∠ACB ∠A=∠ABD ∠C=∠BDC
设∠A=X,
则∠ABD=X ∠C=∠BDC=2X ∠ABC=∠ACB=2X
可列:2X+2X+X=180
X=36
△ABC内各角的度数为A=36度 ∠ABC=∠ACB=72度
∵AB=AC,点D在AC上,且AD=DB=BC
∴∠ABC=∠ACB ∠A=∠ABD ∠C=∠BDC
设∠A=X,
则∠ABD=X ∠C=∠BDC=2X ∠ABC=∠ACB=2X
可列:2X+2X+X=180
X=36
△ABC内各角的度数为A=36度 ∠ABC=∠ACB=72度