In other words, two angles that add up to 90 degrees are known as complementary angles. For example, if angle A is 20 degrees, then its complement angle B would be 70 degrees because 20 degrees + 70 degrees = 90 degrees.

Two angles are Complementary when they add up to 90 degrees (a Right Angle). They don't have to be next to each other, just so long as the total is 90 degrees. Examples: • 40° and 50° are complementary angles. • 60° and 30° are complementary angles. • 5° and 85° are complementary angles.

Complementary angles add up to 90° - example: 15° & 75° are complementary (added together, they form a right angle) -and- Supplementary angles add up to 180° - example: 50° & 130° are supplementary (added together, they form a straight line)

Common examples of complementary angles are: Two angles measuring 45 degrees each. Angles measuring 30 and 60 degrees. Angles measuring 1 degree and 89 degrees. A complimentary angle can be adjacent angles. For example, ∠ STA= 65 degrees and ∠ATR= 25 degrees are adjacent complementary angles.

In right triangle ABC above, ∠B = 90° and ∠A + ∠C = 90° so, the nonadjacent angles A and C are complements of each other. You can determine the complement of a given angle by subtracting it from 90°. For example, the complement of 28° is 62° since 90° - 28° = 62°.