Answer:
x = 39
Step-by-step explanation:
The angle between a tangent and the radius of a circle at the point of contact is 90° , then
x = 180 - (90 + 51) = 180 - 141 ← angle sum of triangle
x = 180 - 141 = 39
x + 51 = 90
x = 90 - 51
x = 39°
