Answer:
As shown in picture, the circle is divided into 2 arcs, one of them is 142 deg.
Then the other one A is 360 - 142 = 218 deg (property of sum of all arcs on circle).
As the property of angle created by a tangent line:
x = (1/2) x arc A = (1/2) x 218 = 109 deg
Hope this helps!
:)