Question

Need help finding the value of b?

Answer 1

hints:

a+b = 90 degrees since this is formed by the diameter and the tangent line

also, angle 'a' is half of 54 degrees by the inscribed angle theorem

Answer 2

to complete your answer, now you wil be able to find "a"
which is "a" = 54/2 = 27

now a+ b = 90 (see previous posts here)
b = 90 -a = 90 - 27 = 63 degrees.