Radian Definition Dynamic Demonstration

①This example dynamically demonstrates the definition of a radian using a unit circle: the radian measure of an angle equals the ratio of the arc length to the radius.②Core mathematical concepts include radian measure, unit circle, central angle, arc length, and the relationship between degrees and radians.③Construction highlights: using GeoGebra commands such as Circle to create the unit circle, Point and Rotate to place points, CircleArc to draw the arc, Angle to measure angle α, Distance to compute arc length, and Segment/Intersect for auxiliary constructions; a slider or button allows dynamic adjustment of the angle, showing that the ratio of arc length to radius remains equal to the angle in radians.④Suitable for high school or introductory college students learning trigonometry and angle measurement, and useful for classroom demonstrations or self-study of the geometric meaning of radians.