Step-by-step explanation:
[tex]in \: \triangle \: CDE \: \\ \\ \overline {EC} \cong \:\overline {DE}....(given) \\ \\ \therefore \: \angle \: C \cong \: \angle \:D...(1) \\ \\ \because \: \angle \: C + \angle \:D + \angle \: E = 180 \degree...(2) \\ \\ \therefore \: from \: equations \: (1) \: and \: (2) \\ \\ \angle \:D + \angle \:D + \angle \: E = 180 \degree \\ \\ \therefore \: 2\angle \:D + 109 \degree = 180 \degree \\ \\ \therefore \: 2\angle \:D = 180 \degree - 109 \degree \\ \\ \therefore \: 2\angle D = 71 \degree \\ \\ \therefore \: \angle D = \frac{71 \degree}{2} \\ \\ \huge \red{ \boxed{\therefore \: \angle D =35.5\degree}}[/tex]
