Question

如图,在△ABC中,AB=AC,点D在AC上,且BD=BC=AD,则∠ABD=()

要答案，要图画

Answer 1

解： AB=AC   所以∠1=∠3+∠4

       BD=BC=AD  所以 ∠1=∠2，∠4=∠5

       ∠2=∠4 +∠5

      即：∠3+∠4=∠4+∠5     ∠3=∠5∠4

      在三角形BCD中 ∠1+∠2+∠3=180°

      即 ：(∠3+∠4)+(∠4+∠5)+∠3=180°

              5*∠4=180°

               ∠4=36°

          即∠ABD=36°

Answer 2

36°