Point Symmetry

Date: 08/19/2001 at 02:24:35
From: tammy
Subject: Geometry

What exactly is point symmetry? How can one tell if point symmetry is 
present?

Date: 08/19/2001 at 15:30:16
From: Doctor Sarah
Subject: Re: geometry

Hi Tammy - thanks for writing to Dr. Math.

You can read about point symmetry and study some good diagrams at the 
New York State Regents Exam Prep Center:

   An Intuitive Notion of Point Symmetry
   http://regentsprep.org/Regents/math/symmetry/Psymmet.htm   

   Point symmetry exists when a figure is built around a single 
   point called the center of the figure. For every point in 
   the figure, there is another point found directly opposite it 
   on the other side of the center...

   A simple test to determine whether a figure has point 
   symmetry is to turn it upside-down and see if it looks 
   the same. A figure that has point symmetry is unchanged 
   in appearance by a 180-degree rotation.

- Doctor Sarah, The Math Forum
  http://mathforum.org/dr.math/