Answer:
x = 58
Explanation:
The angle 51° outside the circle whose sides are a tangent and a secant is
equal to half the difference of the intercepted arcs, that is
51 = 0.5 (160 - x) ← multiply both sides by 2
160 - x = 102 ( subtract 160 from both sides )
- x = -58 ( multiply both sides by - 1 )
x = 58