Geometry Definition of an Angle
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What's Your Angle?
Definition of an Angle

 

 Most people know kind of what an angle is.

 You can see them at the point of a slice of pizza ...
 

 

 
 The "lift" in a skateboard jump ramp ...
 

 

 
 and stuff like that all have angles we know about.
 
 To get really technical,
 if you take two different rays that start at the same point
 you get an angle ...
 

 

 
 There are lots of ways to measure angles.
 The way that gets used the most is called degrees.
 
 Why do they call it degrees?
 Who knows! 
 And who really cares?
 
 They could have called it anything,
 degrees is just a name.
 
 The important thing is how it works.
 
 It works kind of like a crazy watch that runs backwards.
 
 Example:
 Start with a ray at 3 O'clock ...
 

 

 
 Now put another ray at 12 O'clock.
 

 

 
 The angle measure from the 3 O'clock ray 
 to the 12 O'clock ray ...
 

 

 
 Now take away the ray at 12 O'clock 
 and put in one at 9 O'clock ...
 

 

 
 There are 3 hours from 12 O'clock to 3 O'clock
 and 90 degrees.
 There are 6 hours from 9 O'clock to 3 O'clock.
 Guess how many degrees it is?
 

 

 
 Now take away the ray at 9 O'clock 
 and put one in at 6 O'clock.
 
 It's 9 hours from 6 O'clock to 3 O'clock
 How many degrees do you think it is?
 

 

 
 How many degrees do you think it would be from 12 O'clock
 back around to 12 O'clock again?
 

   copyright 2005 Bruce Kirkpatrick

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