Answer:
30
Explanation:
Look at the image I attached for reference as I explain. (I only labeled the angles that are relevant to the problem)
These triangles are congruent, as shown by the first equation.
When triangles are congruent, it means that the sides and angles are the same.
We can see that angles ∠ABC and ∠DEC are corresponding, which means that they have the same value.
We don't know ∠DEC, but we have two angles in that triangle that we do know. Since the angles in a triangle add up to 180, we have this equation:
180-65-55=∠DEC
60 = ∠DEC
So now we know that ∠DEC is 60 degrees.
Since ∠ABC and ∠DEC are equal:
2x=60.
Divide both sides by 2, and we get x =30.