III. State whether the statement is always true (AT), sometimes true (ST) or never true (NT).
Angles with a common side and vertex but no interior points are
2. The supplement of an angle is acute. (ST)
3. The complement of an angle is obtuse.(NT)
4. The complement of any acute angle is acute. (AT)
5. Two intersecting lines form two pairs of vertical angles.(AT)
6. Two supplementary angles are congruent. (ST)
7. Angles that form a linear pair are supplementary.(AT)
8. Supplementary angles form a linear pair. (ST)
9. Two adjacent angles form a linear pair. (ST)