BD=DE,则∠DBE=∠DEB,设∠DBE=∠DEB=X(度),则∠ADE=∠DBE+∠DEB=2X.
DE=AE,则∠A=∠ADE=2X;∠BEC=∠A+∠DBE=3X.
BE=BC,则∠C=∠BEC=3X.
又AB=AC,则∠ABC=∠C=3X.
∠A+∠ABC+∠C=180度,即2X+3X+3X=180度,2X=45.-----------------即∠A=45度.
BD=DE,则∠DBE=∠DEB,设∠DBE=∠DEB=X(度),则∠ADE=∠DBE+∠DEB=2X.
DE=AE,则∠A=∠ADE=2X;∠BEC=∠A+∠DBE=3X.
BE=BC,则∠C=∠BEC=3X.
又AB=AC,则∠ABC=∠C=3X.
∠A+∠ABC+∠C=180度,即2X+3X+3X=180度,2X=45.-----------------即∠A=45度.