Let P(4,0) and Q(0,5) be two points in the plane.
A line L1 passes through P and is inclined at 45∘ to the positive x-axis. A second line L2 passes through Q and is perpendicular to L1.
(i) Find the equations of L1 and L2.
(ii) A line L3 is drawn through Q parallel to L1 and a line L4 is drawn through P parallel to L2. Obtain the equations of L3 and L4.
(iii) The four lines L1,L2,L3,L4 enclose a quadrilateral. Prove that this quadrilateral is a rectangle and calculate its area.