Respuesta :

ΔADC ≅ ΔBCD (SAS congruency)

∠AED ≅ ∠BEC (opposite angles)

ΔAED ≅ ΔBEC (ASA congruency)

Therefore DE ≅ CE (corresponding sides of the two congruent triangles AED and BEC)

ΔADC ≅ ΔBCD (SAS theorem)

∠AED ≅ ∠BEC (opposite angles )

ΔAED ≅ ΔBEC (ASA congruency postulate)

Therefore DE ≅ CE (CPCTC: Corresponding Parts of a Congruent Triangle are congruent)

hope this helps