Answer: A. There all 90 degrees
Explanation:
Given: Three parallel lines are cut by a transversal and one angle is measured to be 90 degrees.
We know that if two lines cut by transversal the following pairs are equal:
- Vertically opposite angles.
- Corresponding angles.
- Alternate interior angles.
- Alternate exterior angles.
If one angles measures 90°, then its supplement would be 90°.
Then by using above properties , we will get measure of all angles as 90°.