Rectangle with quadrilateral drawn betweens points on each side.

Show that, for any values of x and y where x>y,

  1. the angle SPQ is always the same and find this angle
  2. the angle SRQ is always the same and find this angle
  3. the quadrilateral SPQR is cyclic
  4. the angle PQR is always the same and find this angle
  5. the angle PSR is always the same and find this angle.