Sector Area (Degrees) Visualization with the Unit Circle

This example visualizes how the area of a circular sector changes as the central angle varies when the angle is measured in degrees. It highlights the geometric relationship between sector area, arc length, and the full circle: Area = (θ/360°)·πr², and corresponding proportionality between sector area and the circle’s circumference (or between arc length and circumference). The construction uses GeoGebra commands to draw a circle (Circle), place key points (Point), define the radius and central angle (Segment, Angle), create the arc/sector boundary (CircleArc, CircleSector), and compute quantitative results (Area for sector area, Length for arc length, Circumference for the full circle). Labeled objects (e.g., Sector, SectorArea) and text readouts report the computed area and related values. Suitable for secondary-level geometry lessons and early college instruction, especially for building intuition with the unit circle and degree-based angle measurements.