In the given figure, angle 156° is an exterior angle
From the property of exterior angle :
The exterior angle theorem states that the measure of each exterior angle of a triangle is equal to the sum of the opposite and non-adjacent interior angles
From the properties we can concluded that :
156 = x + 55
Simplify for the x :
x + 55° = 156°
x = 156° - 55°
x = 101°
The value of x is 101°
Answer : x = 101°