Constructing Perpendicular Lines in the Plane with Angle Verification

This GeoGebra example demonstrates how to construct a perpendicular line in the plane relative to given geometric elements, and how to visually verify the perpendicular condition using angle relationships. The key math concepts include perpendicular lines and the criterion for perpendicularity, angle concepts in planar geometry, and geometric constraints that make the construction stable for inspection. Construction focuses on creating foundational segments using GeoGebra’s geometric tools: the provided summary indicates using the “Segment” command to build segment objects corresponding to A, B, C, D and additional constructed elements f, g, h, i. These segments form the reference directions, enabling students to check whether the resulting angles represent right angles. Suitable for middle and high school geometry lessons, classroom demonstrations, and interactive practice on perpendicular constructions and angle properties.