Final answer:
The term that correctly describes the statement "Vertical angles are always congruent" is Congruent angles. Vertical angles are equal in measure when two lines intersect, making the correct answer C) Congruent angles.
Step-by-step explanation:
The term that best describes the statement "Vertical angles are always congruent" is Congruent angles. Vertical angles are the angles opposite each other when two lines intersect. They are equal in measure, hence they are congruent. For example, if two intersecting lines form one angle of 120°, its vertical angle is also 120°.
The options provided refer to different types of angles:
- Supplementary angles are two angles whose sum is 180°.
- Complementary angles are two angles whose sum is 90°.
- Congruent angles are angles that are equal in measure.
- Adjacent angles are two angles that have a common side and a common vertex (corner point) and don't overlap.