Answer:
Option A) angle B = 67°
Step-by-step explanation:
I'll use " [ " symbol for saying angle.
Alright so ...
since triangle ABC and triangle DEF are congruent
it means [ A = [ D
[ B = [ E
[ C = [ F
here [ A = 78° (which means [ D is also 78°)
and ..[ F = 35° (which means [ C is also 35°)
-->So now all you need to know to find [ B is to know the other two angles in the triangle. and thats where ..
you write.. [ A + [ B + [ C = 180° (angle sum property)
78° + [ B + 35° = 180°
113° + [ B = 180°
[ B = 180 - 113
= 67°
I hope that clears the concept , if you have any questions regarding it I'd love to help .
