Answer x = 25°
In triangle ABC
Angle BAC = BCA
= 50
Because its isoceles triangle and base angles are equal.
x + x + 80 = 180
2x = 100
x = 50
Angle ACD is exterior angle so 80 + 50
= 130
Triangle ACD is also Isoceles Angle x = Angle CDA
130 + x + x = 180
2x = 50
x = 25