References: 1  Royal College of Radiologists. 2  Swinson S, Tapp M, Brindley R, Chapman S, Offiah A, Johnson K. An audit of skeletal surveys for suspected non-accidental injury following publication of the British Society of Paediatric Radiology guidelines. 3  Offiah AC, Hall CM.
The question of distance between two straight lines arises only when they are parallel. The given lines are parallel. If the equations of parallel lines are ax + by + c = 0 and ax + by + c' = 0, then the perpendicular distance between them is given by. p = l c - c' l / sqrt ( a^2 + b^2 )
More Geometry Lessons. Parallel and Skew Lines. Parallel lines are two lines in the same plane that never intersect. In a coordinate plane, parallel lines can be identified as having equivalent slopes. Parallel lines are traditionally marked in diagrams using a corresponding number of chevrons (or arrows).