Q. In the alongside diagram, the bisectors of interior angles of the parallelogram PQRS enclose a quadrilateral ABCD.

Show that : 
(i) $\angle$PSB+$\angle$SPB = 90$°$    (ii) $\angle$PBS = 90$°$    (iii) $\angle$ABC = 90$°$       (iv)  $\angle$ADC = 90$°$
(v) $\angle$A = 90$°$       (vi)  ABCD is a rectangle