FTCE General Knowledge Math Practice Test

Which of the following indicates the relationship of angles that add up to 90 degrees?

1. Congruent angles

2. Complementary angles

3. Supplementary angles

4. Scalene angles

The correct answer is: Complementary angles

The correct choice is indeed the one that refers to complementary angles. Complementary angles are defined as two angles whose measures add up to 90 degrees. This relationship is fundamental in geometry, especially when dealing with right angles and various applications in trigonometry and geometric proofs. Congruent angles, on the other hand, refer to angles that have the same measure but do not necessarily add up to any specific value. Supplementary angles are those that sum to 180 degrees, which is different from the requirement of adding to 90 degrees. Scalene angles relate to triangles and imply that all sides and angles in a triangle are of different lengths and measures, providing no relevance to angle relationships summing to any specific degree. Thus, when looking for angles that total 90 degrees, complementary angles are the correct terminology and concept.