please help

1)  Since Z is the center of the circle, arc(BC) = angle(BZC)   --->   arc(BC) = .......^o

 

2)  Since angle(BAC) cuts off arc(BC), angle(BAC) = ½·arc(BC)   --->   angle(BAC) = .......^o 

 

3)  Since AB || CD, angle(DCA) = angle(BAC)   --->   angle(DCA) = .......^o