Chang's Math blog

Yes, complementary and supplementary angles are entirely legitimate, standard terms in mathematical language, specifically within the field of geometry.

These terms are used to define special pairs of angles based on their sum of measurements:

Complementary Angles: Two angles whose measures add up to exactly 90 degrees (forming a right angle).
Supplementary Angles: Two angles whose measures add up to exactly 180 degrees (forming a straight line).

Key Characteristics

Pairs Only: Both definitions specifically apply only to two angles. Three or more angles whose sum is 90° or 180° are not technically considered complementary or supplementary, respectively.
No Adjacency Required: The angles do not need to be physically connected or adjacent in a diagram. As long as their measures add up to the required total (90° or 180°), they are considered complementary or supplementary.
Acute/Obtuse Restrictions:
- Complementary angles must both be acute (less than 90°).
- Supplementary angles can be two right angles, or one acute angle and one obtuse angle.