Measure of ∠y is 90°
Step-by-step explanation:
We see that,
∠x and ∠y are vertical angles and ∠x, 40°, 50° are in a straight line.
Since, we know, Sum of angles in straight line is 180°.
Then, ∠x + 40° + 50° = 180°
i.e. ∠x = 180° - 90°
i.e. ∠x = 90°
Also, we know, 'Vertical angles have equal measures'.
So, ∠y = ∠x = 90°
Hence, measure of ∠y is 90°