Draw any line segment . Mark any point on it. Through , draw a perpendicular to (use ruler and compasses).
Step 1. Draw a line segment and mark a point on it as the first step.
Step 2. Next, construct an arc intersecting the line segment at points and , using as the center and a convenient radius.
Step 3. Finally, construct two arcs with and as centers and a radius bigger than so that they intersect at point .
Step 4. The final step is to join . has now become perpendicular to .
Hence, the diagram is shown below: