Answer:
100°
Step-by-step explanation:
The sum of the 3 angles in a triangle = 180°, thus
∠ACB = 180° - (90 + 50)° = 180° - 140° = 40°
∠ECD = 40° ( vertical angle to ∠ACB )
Since CE ≅ ED then ΔCDE is isosceles and
∠CDE = ∠ECD = 40°
∠E = 180° - (40 + 40)° = 180° - 80° = 100°
