Straight Line - Distance Form

The equation of a straight line passing through (x₁,y₁) and making an angle θ with the positive direction of x – axis is 
                              (x-x₁)/cosθ = (y-y₁)/sinθ=r , 
where r is the distance of the point (x,y) on the line from the point (x₁,y₁).
  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