If one angle of a linear pair is acute, then its other angle will be:
Answer: B
A linear pair of angles are adjacent angles whose non-common sides are opposite rays. Their sum is always 180°.
An acute angle is less than 90°. Let the acute angle be x, where x < 90°.
The other angle will be 180° - x.
Since x < 90°, then 180° - x > 90°. An angle greater than 90° is an obtuse angle.