Steps of Construction-

1. Draw a ray OA

2. Taking O as centre and convenient radius, mark an arc, which intersects OA at X.

3. Taking X as centre and same radius, cut previous arc at Y. Taking Y as centre and same radius, draw another arc intersecting the same arc at Z.

4. Taking Y and Z as centers and same radius, draw two arcs intersecting each other at S. Join OS. Thus, ∠SOA is required angle of 90°.

5. Draw the bisector of ∠BOA. Hence, ∠MOA = 45°

6. Draw the bisector of ∠MOA. Hence,