Elements of Synthetic Solid Geometry

AB² ABCD altitude axis base bisect bisector centroid chord circle circular cone common line complanar congruent conic cos² cube cuboid curve cylinder cylindroid denote diagonals diameter dihedral angles draw ellipse equal face angles form a sheaf four frustum given line given point Hence hyperbola infinity intersection isoclinal line join line-segment locus mean centre median meet middle point mon line non-complanar lines normal number of faces octahedron opposite parabola parallel lines parallelepiped parallelogram pass perpendicular planar line plane figure plane geometry point equidistant polygon polyhedra polyhedron prism prismatoid projection Proof pyramid radius rectangle right angle right section right-bisector plane ruled surfaces segment sheaf of lines sides skew quadrilateral spatial figure sphere spheric geometry spheric line spheric triangle squares surface tangent line Theorem three-faced corner vertex vertices volume