Geometry
Angle Calculator
Lets users solve and check angle instantly with formula, steps and examples — no manual math.
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°
Your result
Reference angle
30 °
210° → coterminal 210°, reference angle 30° (Quadrant 3).
Coterminal (0–360°)
210 °
Quadrant
Quadrant 3
About this calculator
A reference angle is the acute angle between the terminal side and the x-axis. Reduce to 0–360° first, then: Q1 = θ, Q2 = 180−θ, Q3 = θ−180, Q4 = 360−θ.
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