if y=12 and x=89, then what is the value of z?

Answer:
z = 166°
Step-by-step explanation:
Given:
x = 89
y = 12
An angle with its vertex in a circle = ½(intercepted arcs)
Thus:
x = ½(y + z)
Substitute
89 = ½(12 + z)
Multiply both sides by 2
2(89) = 12 + z
178 = 12 + z
178 - 12 = z
z = 166°