Answer:
57
Step-by-step explanation:
An angle formed by a tangent and secant is equal to half the difference of its intercepted arcs. ( major arc minus minor arc to be more specific. )
∠B is the angle formed by a tangent and secant
Arc CA is its intercepted arc ( minor arc to be more specific )
Arc DA is also its intercepted arc ( major arc to be more specific )
Hence, ∠B = [tex]\frac{1}{2}[/tex] ( Arc DA - Arc CA )
If arc CA = 51 and Arc DA = 165
Then ∠B =
[tex]\frac{1}{2} (165-51)\\165 - 51=114\\\frac{1}{2} (114)=57[/tex]
Hence, ∠B = 57
