The correct option is A 80
Given,
△ABC≅△XYZ
and
∠BCA=∠YZX ... (given)
BC=YZ ... (given)
Since △ABC≅△XYZ,
We know that, the corresponding parts of congruent triangles are equal.
So, ∠CAB=∠ZXY =30∘
In △ABC,
∠CAB+∠ABC+∠BCA=180∘
⇒30∘+x+70∘=180∘
x=(180∘−30∘−70∘)=80∘