Following are the steps for construction of a perpendicular to a line from a point outside it. In this construction, the arcs are shown as circles.
- Let AB be the given line and P is the point outside it
- With A as centre and radius AP, draw an arc cutting the given line at C.
- With C as centre and radius CP, draw an arc cutting the arc of step 2 at R.
- Draw line segment joining PR intersecting AB at Q.