+The **Unit Circle** is a circle with a radius of one, centered at the [Origin](/wiki/origin) of the [Cartesian Coordinate System](/wiki/cartesian_coordinate_system). It is a fundamental tool in [Trigonometry](/wiki/trigonometry), elegantly mapping angles to their sine and cosine values, and forming the basis for understanding periodic functions.
+## See also
+- [Radius](/wiki/radius)
+- [Angle](/wiki/angle)
+- [Sine](/wiki/sine)
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