Steps of Construction-

1. Draw a line l and mark a point O on it.

2. Place the pointer of the compasses at O and draw an arc of any radius which intersects the line l at A.

3. Taking same radius, with centre A, cut the previous arc at B.

4. Join OB, then ∠BOA = 60°.

5. Taking same radius, with centre B, cut the previous arc at C.

6. Draw bisector of ∠BOC. The angle is of 90°. Mark it at D. Thus, ∠DOA = 90°

7. Draw OP as bisector of ∠DOB.

8. Thus, ∠POA = 75°