- S6 3D Basic Concept1.1 Perpendicularity of a Line and a Plane1.2 Perpendicularity of a Vertical Edge of the CuboidShadow and Projectionbox diagonalQuiz on Projection of a Line Segment on a Plane 投影：測驗Angle between a Line and a PlaneAngle between a Line and a Plane 投影與線面角Angle between 2 Planesprojection of a segmentopening a doorAngle between a Line and a PlaneSlope of an Inclined PlaneAngle between Lateral Faces 1Angle between Lateral Faces 2Angle between Lateral Faces 3Pyramid with a Vertical PoleAngle between 2 planes in a cube
