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Corresponding Angles

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• Meaning of "Parallel"
  
  
  • The meaning of "parallel" is "of the same direction".
    
    
  • The way of judging if two straight lines are "of the same direction" or not is the following :
    
    
    1. Introducing a "horizon"
    2. Comparing the inclinations of two straight lines relative to the "horizon"

And here "corresponding angles" becomes a sucject.


• If two lines intersect each other, then corresponding angles are of different magnitudes.
  Therefore, if corresponding angles are of the same magnitude, they do not intersect each other, or parallel to each other.

• Parallelims of line segments, rays
  
  
  • Two line segments/rays are said parallel to each other, if their extensions to straight lines are parallel.
  
  
• Reference
  
  
  • Euclid's Axiom