Answer:
A
Step-by-step explanation:
XY = XZ = 6
Thus the triangle is isosceles with base angles congruent, that is
∠Y = ∠Z = 70°
The sum of the 3 angles in the triangle = 180°, thus
∠X = 180° - (70 + 70)° = 180° - 140° = 40° → A
