Let be given a semi-sphere Σ whose base-circle lies on plane p. A variable plane Q, parallel to a fixed plane non-perpendicular to P, cuts Σ at a circle C. We denote by C′ the orthogonal projection of C onto P. Find the position of Q for which the cylinder with bases C and C′ has the maximum volume. inequalitiesgeometryGeometric Inequalities3D geometry