IN the diagram above POQ is a diameter of the c... - JAMB Mathematics 2006 Question

∠PSQ = 90^o (∠ in semi circle)
∠PSQ + ∠QSR = 145^o
90 + ∠QSR = 145
∠QSR = 145 - 90
∠QSR = 55^o
BUt x^o = ∠QSR (∠s in the same segment)
∴x^o = 55^o