题目没交代清楚
=AE.
莫非是AD=AE 以及AB=BE
证明:
∵AB = AE,∠BAE =70°
∴∠B = (180°-70°×2)=40°
∵AB =AC
∴∠C = 40°
∴∠BAC = 100°
∴∠EAD = 30°
∵AE=AD
∴∠ADE = (180°-30°)/2=75°
∵∠ADE = ∠DEC+∠C
∴∠DEC = 75°-40°=35°
题目没交代清楚
=AE.
莫非是AD=AE 以及AB=BE
证明:
∵AB = AE,∠BAE =70°
∴∠B = (180°-70°×2)=40°
∵AB =AC
∴∠C = 40°
∴∠BAC = 100°
∴∠EAD = 30°
∵AE=AD
∴∠ADE = (180°-30°)/2=75°
∵∠ADE = ∠DEC+∠C
∴∠DEC = 75°-40°=35°