Geometric Construction of the Angle of Inclination

This example visualizes the geometric meaning of the angle of inclination (the direction angle of a line) and highlights how the measured angle changes through clear on-screen labeling. Key concepts include the angle of inclination tied to a line’s direction, angle construction and annotation, and continuity of geometric measurements as defining elements vary. Construction highlights from the provided GeoGebra command set: Point is used to create the defining points (e.g., A, B and related objects), If drives conditional logic to choose a configuration or update the construction, Angle computes the inclination angle (e.g., the angle α), and Text adds descriptive labels (text objects such as text1/text2/text3/text5/text6) to present the result and guide interpretation. Suitable for secondary to early undergraduate geometry/coordinate-geometry instruction, especially for teaching slope-to-angle relationships, direction of lines, and practical geometric construction skills in GeoGebra.