March 13th, 2016, 12:08 AM  #1 
Senior Member Joined: Oct 2013 From: Far far away Posts: 422 Thanks: 18  test for perpendicular lines.
Two lines m and n intersecting at point P are perpendicular if and only if when m is folded onto itself at point P the line n lies on the foldline. Explain. My attempt: When we fold m onto itself at P a foldline forms at P. This foldline is like an axis of reflection symmetry for the line. This implies that the angles formed at P are congruent. Therefore the foldline is perpendicular to line m. Now if line n lies along the foldline it implies line n too is perpendicular to m. Am I correct? Is there a better explanation? Thanks. 
March 13th, 2016, 07:20 PM  #2 
Senior Member Joined: Dec 2012 From: Hong Kong Posts: 853 Thanks: 311 Math Focus: Stochastic processes, statistical inference, data mining, computational linguistics 
Yep, that's correct 

Tags 
lines, perpendicular, test 
Thread Tools  
Display Modes  

Similar Threads  
Thread  Thread Starter  Forum  Replies  Last Post 
perpendicular lines  MrBoat  Geometry  2  April 5th, 2014 12:14 PM 
Perpendicular Lines  poochie03  Algebra  3  November 10th, 2011 03:55 AM 
Parallel and perpendicular lines.  Eftychia  Algebra  2  February 27th, 2011 07:38 AM 
Parallel and Perpendicular Lines  cafegurl  Algebra  3  July 25th, 2010 05:03 PM 
Perpendicular Lines  poochie03  New Users  0  December 31st, 1969 04:00 PM 