Intersecting Planes in 3D Geometry

① This GeoGebra example demonstrates the intersection of two planes in 3D space, showing how they meet along a line. ② Core mathematical concepts include solid geometry, relative positions of planes, the line of intersection, and the relationship between spatial points and plane equations. ③ Construction: Based on the summary, the Point command creates points A, B, C, D, E; the Plane command defines plane a through A, B, C; and PointIn places points within planes, building two intersecting planes and their intersection structure. ④ Suitable for high school solid geometry or introductory university analytic geometry, helping students visualize plane intersections and connect geometric intuition with algebraic representations.