A Line Perpendicular to a Plane

① This example demonstrates how to construct a line perpendicular to a given plane in 3D space, showing the foot of the perpendicular and the right angle clearly. ② The core mathematical concept is the line-plane perpendicularity in solid geometry: a line is perpendicular to a plane if it is perpendicular to two intersecting lines in that plane; it also involves the foot of the perpendicular and orthogonal relations in space. ③ Construction details: using GeoGebra commands Plane to create plane α, OrthogonalLine to draw the perpendicular line from point D to the plane, Point to mark the foot, and Angle to label the right angle; objects include points A, B, C, D, line f, and plane α. ④ Suitable for high school solid geometry lessons or introductory spatial analytic geometry in college, helping students understand the geometric construction and dynamic verification of line-plane perpendicularity, and useful for teachers creating interactive materials.