Two right angles are complementary to each other.
One obtuse angle and one acute angle can make a pair of complementary angles.
Two supplementary angles are always obtuse angles.
Two right angles are always supplementary to each other.
One obtuse angle and one acute angle can make a pair of supplementary angles.
Both angles of a pair of supplementary angles can never be acute angles.
Two supplementary angles always form a linear pair.
Two angles making a linear pair are always supplementary.
Two angles making a linear pair are always adjacent angles.
Vertically opposite angles form a linear pair.
Interior angles on the same side of a transversal with two distinct parallel lines are complementary angles.
Vertically opposite angles are either both acute angles or both obtuse angles.
A linear pair may have two acute angles.
An angle is more than 45°. Its complementary angle must be less than 45°.
Two adjacent angles always form a linear pair.