Answer:
b= 126°
Step-by-step explanation:
OC= OB (radius of circle)
∠OCB= ∠OBC (base ∠s isos. △)
a= 27°
b= 180° -27° -27° (∠ sum of △OBC)
b= 2c (∠ at centre= 2 ∠ at circumference)
c= b/2 (divide by 2 on both sides)
c= 126° ÷2
c= 63°
