Perpendicular to a Line - 4

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. 

1. Let AB be the given line and P is the point outside it 
2. With A as centre and radius AP, draw an arc cutting the given line at C. 
3. With C as centre and radius CP, draw an arc cutting the arc of step 2 at R. 
4. Draw line segment joining PR intersecting AB at Q.

PQ is the required perpendicular. Drag Point P and see the effect. This is a Java Applet created using GeoGebra from www.geogebra.org - it looks like you don't have Java installed, please go to www.java.com