Angle Between Two Planes: Dynamic 3D Construction and Measurement

This GeoGebra example demonstrates the dynamic geometric construction and precise measurement of the dihedral angle (angle between two intersecting planes) in three-dimensional space. The core mathematical concepts covered include spatial planes, normal vectors, the definition of plane angles, trigonometric functions, and analytic geometry concerning the positional relationships among points, lines, and planes in 3D. Based on the construction summary, the example uses the Polygon command to create two planar polygons poly1 and poly2, Point to establish spatial reference points such as A, B, C, and D, OrthogonalLine and OrthogonalPlane to construct perpendicular lines and planes, Intersect to compute the intersection line of the planes, Angle to measure angles α, β, γ, and δ, and Segment to draw auxiliary line segments. It is suitable for high school solid geometry instruction, college engineering drawing, and introductory computer graphics courses, helping learners intuitively understand and calculate the angle between two planes.