Answer:
Step-by-step explanation:
The identical arc symbols on the two angles indicates the angles are congruent. Also, these are alternate interior angles where a transversal crosses lines marked as parallel, so they are congruent:
∠A = ∠B
8x +78° = 2x +114° . . . . . substitute the given expressions
6x = 36° . . . . . . . . . . . . . subtract 2x+78° from both sides
x = 6° . . . . . . divide by 6
∠B = 2x +114° = 2·6° +114° . . . . . put the value of x into the expression
∠B = 126°
