Answer:
57
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 =
( Arc DA - Arc CA )
If arc CA = 51 and Arc DA = 165
Then ∠B =
Hence, ∠B = 57