Answer:
C) 84
Explanation:
side AB is congruent to side AX
this means that the angle ∠A = 4x is the same angle as ∠Z
therefore ∠A = ∠Z = 4x
inside angle of a triangle = 180
∠A + ∠B + ∠Z = 180
4x + 7x + 4x = 180
15x = 180
x = 180/15
x = 12
now substitute x = 12 into angle B
∠B = 7x
∠B = 7 (12)
∠B = 84
therefore, the answer is C) 84