Answer:
m<ECB = 34
Step-by-step explanation:
I will assume that the quadrilateral is a parallelogram because I don't think there is a unique solution without that assumption.
Look at triangle CDE.
The sum of the measures of a triangle is 180 deg.
m<DCE + m<CDE + m<CED = 180
30 + m<CDE + 90 = 180
m<CDE = 60
m<ADC = m<ADE + m<CDE
m<ADC = 56 + 60
m<ADC = 116
m<B = m<ADC = 116
Consecutive angles of a parallelogram are supplementary.
m<ADC + m<BCD = 180
116 + m<BCD = 180
m<BCD = 64
m<BCD = m<ECB + m<ECD
64 = m<ECB + 30
m<ECB = 34
