14.20 - EQUATION OF A SPHERE WHOSE DIAMETER IS THE LINE JOINING TWO GIVEN POINTS14.21 - EQUATION OF A SPHERE PASSING THROUGH FOUR POINTS14.22 - EQUATION OF THE TANGENT PLANE TO A SPHEREM14.23 - CONDITION OF TANGENCY14.24 - ANGLE OF INTERSECTION OF TWO SPHERES14.25 - CONDITION OF ORTHOGONALITY OF TWO SPHERES14.26 - CYLINDER14.27 - EQUATION OF A CYLINDER WITH GIVEN AXIS AND GUIDING CURVES14.28 - RIGHT CIRCULAR CYLINDER14.29 - CONE14.30 - EQUATION OF A CONE WITH ITS VERTEX AT THE ORIGIN14.31 - EQUATION OF A CONE WITH GIVEN VERTEX AND GUIDING CURVE14.32 - RIGHT CIRCULAR CONE14.33 - RIGHT CIRCULAR CONE WITH VERTEX (α, β, γ), SEMI-VERTICAL ANGLE θ, AND THE DIRECTION COSINES OF THE AXIS.14.34 - CONICOIDS14.35 - SHAPE OF AN ELLIPSOID14.36 - SHAPE OF THE HYPERBOLOID OF ONE SHEET14.37 - SHAPE OF THE HYPERBOLOID OF TWO SHEETS14.38 - SHAPE OF THE ELLIPTIC CONE14.39 - INTERSECTION OF A CONICOID AND A LINE14.40 - TANGENT PLANE AT A POINT OF CENTRAL CONICOID14.41 - CONDITION OF TANGENCY14.42 - EQUATION OF NORMAL TO THE CENTRAL CONICOID AT ANY POINT (α, β, γ) ON IT14.43 - MISCELLANEOUS EXAMPLESEXERCISES