Answer:
a = 60
b = 60
Step-by-step explanation:
Vertical angles are congruent to each other
Vertical angle pairs:
AXE = YXC = 30
a = b
BXA = DXC + 90
Line AC is 180 degrees because of definition of a straight line.
This means AXE + b + DXC = 180 (Parts Whole Postulate)
Substitute given angle measurements
30 + b + 90 = 180
b = 180 - 12
b= 60
Since b=a, that means a = 60
Hope this helps :)
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