Answer:
m∠XAZ = 40°
Explanation:
Since ∠YAU, ∠YAZ and ∠XAZ are the angles based at a point on a straight line, and the sum of the all angles on a line is 180°.
Therefore, m∠YAU + m∠YAZ + m∠XAZ = 180°
50° + 90° + m∠XAZ = 180°
m∠XAZ = 180° - 140°
= 40°
Therefore, measure of angle XAZ is 40°.