Oriented Angles and Coterminal Angles on the Unit Circle

This example demonstrates how oriented (directed) angles and coterminal angles can be visualized on the unit circle, making it easy to see that different angle measures can share the same terminal side. Key concepts include directed angles (with positive/negative orientation), coterminal angles, primary angles, and the unit-circle representation that links angles to trigonometric meaning. Construction highlights in GeoGebra: Circle builds the unit circle; Angle and Rotate create and animate the directed angle and its terminal ray; Arc and Segment draw the corresponding positive/negative arcs and key segments (e.g., from the origin to points on the circle); If and Div control angle-range logic to select primary angles and map to coterminal positions; Textfield and Text present interactive values, while InputBox1, SelectedIndex, Element, and Shuffle support user input and dynamic object selection. Suitable for high school through early university learners to explore oriented angles, unit-circle geometry, and trig angle interpretation.