Steps of construction:
(a) Draw a line l and mark a point O on it.
(b) Place the pointer of the compasses at O and draw an arc of any radius which intersects the line l at A.
(c) Taking same radius, with centre A, cut the previous arc at B.
(d) Join OB, then ∠BOA = 60 degree.
(e) Taking same radius, with centre B, cut the previous arc at C.
(f) Draw bisector of ∠BOC. The angle is of 90 degree. . Mark it at D. Thus, ∠DOA = 90 degree.
(g) Draw OP bar as bisector of ∠DOB. Thus, ∠POA = 75 degree.
