Verified answer

concept of similarity and congruences are different. . .

you have already proven that triangle ABC is congruent to triangle RST . .

hence, by CPCTC or corresponding parts of congruent triangle are

congruent . . .then it is always true that angles are also congruent

Are you saying that the triangles ABC and RST are congruent? If so, Then everything will be congruent including sides and angles. If they are similar then too, you can say that all the angles are congruent.

Yes,it's true.

Because,According to The case of equality of triangles,

When we prove two triangles are equal to each other,We can write the equality of other components of the corresponding two triangles, that One of them is the equality of three angles.