How this calculation works
Find the acute reference angle and the angle that sums with the input to 180°.
THE FORMULA
Normalize to one turn and measure the distance to the nearest x-axis rayA worked example
210° has reference angle 30° and a signed supplement of −30°.
Good to know
Quadrantal inputs can give 0° or 90°.
Reference: OpenStax Algebra and Trigonometry (opens in a new tab) ↗
Read the result
Find the acute reference angle and the angle that sums with the input to 180°.
The primary result is labeled “Reference angle (°)”. Keep the input definitions in view when comparing this result with another method.
Try a related calculation
Quadrantal inputs can give 0° or 90°.
For a related exercise, try the quadratic equation solver.
A few questions, answered
How can I check the default inputs by hand?
210° has reference angle 30° and a signed supplement of −30°.
Which rule does this calculator apply?
Normalize to one turn and measure the distance to the nearest x-axis ray