Question

If triangle abc equal def and angle a =50 angle f=60 then angle b

Answer 1

hope it is correct☺☺☺☺

Answer 2

triangle ABC congruent to triangle DEF.
angle A = angle D
angle B = angle E
angle C = angle F

therefore, In triangle ABC,
angle A + angle B + angle C = 180°
ie; 50° + angle B + 60° = 180°
angle B = 180° - 110°
angle B = 70°

Hope it is clear for you.
If you have any doubts don't forget to ask me.