How this calculator works
Supplements divide a straight angle. Adjacent supplementary angles form a straight line, but angles do not need to be adjacent to have a sum of 180 degrees. Choose find to subtract one angle from the target sum, or check to test two measures. Nonnegative angles through the target are accepted, including a zero angle at the boundary. Comparisons allow a tolerance of 10^-10 radians to absorb unit conversion rounding.
Formula
For supplementary angles, alpha + beta = 180 degrees. Therefore beta = 180 degrees - alpha.
Worked example
A 30 degree angle has a 150 degree supplement. Two right angles are supplementary because 90 + 90 = 180.
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Frequently asked questions
Can I enter radians?
Yes. The target sum is pi radians, and every supported unit converts before the calculation.
What if my angle is too large?
An angle greater than 180 degrees has no nonnegative supplementary partner in this calculator. An inline error asks for a measure in range.
Are zero angles allowed?
Yes. The boundary pair is 0 degrees and 180 degrees. Some classes restrict the term to positive angles; follow that convention if required.