Two angles are complementary if the sum of their angles equals 90^{o}.

If one angle is known, its complementary angle can be found by subtracting the
measure of its angle from 90^{o}.

Example: What is the complementary angle of 43^{o}?

Solution: 90^{o} - 43^{o} = 47^{o}

Two angles are supplementary if the sum of their angles equals 180^{o}.

If one angle is known, its supplementary angle can be found by subtracting the
measure of its angle from 180^{o}.

Example: What is the supplementary angle of 143^{o}?

Solution: 180^{o} - 143^{o} = 37^{o}