x = 70 degrees
The reason for that is the triangle has 2 congruent sides, which means it’s isosceles. Isosceles triangles have congruent base sides, so we can find out the other missing angle, which is also 55.
Add the 2 base angles (55+55) to get 110. Then, do 180-110 to find x because all angles inside a triangle add to 180