Practice: Construct Perpendicular Lines in the Plane (90° Verification)

This example demonstrates how to construct perpendicular lines in the plane by creating a line that forms a 90° angle with a given line through a specified point (or an endpoint). It focuses on the geometric phenomenon of establishing and checking perpendicularity using angle measurement. Key concepts include perpendicular lines, the intersection angle between two lines, and angle verification as a geometric constraint. The construction typically involves creating the given points and lines, applying GeoGebra’s geometric construction tools to draw the perpendicular line (e.g., “perpendicular line through a point”), and then using an Angle object to measure/confirm that the relevant angle is a right angle (90°). The resulting perpendicular relations can also support studying quadrilateral configurations (such as verifying conditions related to parallelograms). Suitable for middle school geometry instruction and geometry construction practice.