Answer:
Angle EDC = 180 - 90 - 30 = 60° (sum of angles in triangle add up to 180°)
Angle ADC + angle DCB = 180° (interior angles, AB//CD)
59 + 60 + 30 + angle ECB = 180
Angle ECB = 180 - 59 - 60 - 30 = 31°
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