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Reference Angle Calculator
Calculate the acute reference angle for any given angle in degrees
Formula: A reference angle is the acute angle ($\le 90^\circ$) made with the x-axis. Quadrant rules (after normalizing angle $0^\circ \le \theta < 360^\circ$): Q1 ($\theta$); Q2 ($180^\circ - \theta$); Q3 ($\theta - 180^\circ$); Q4 ($360^\circ - \theta$). Enter angle below.
Angle Input
Calculation Results
⚠️ For educational purposes only. Verify results with a qualified professional when making important decisions.