Let B and T be the bottom and top of the screen, respectively. Let V be the position of the viewer’s eye; and, let P be the point that is horizontally across from V such that VP is perpendicular to the screen (see figure at right). Then it can be determined that \({\rm{PV}} = 3 + x\cos \alpha \), \({\rm{PT}} = 10.8 - x\sin \alpha \) and \({\rm{PB}} = - 2.3 + x\sin \alpha \).View the solution presented in the PDF file below (downloadable).