Difference between revisions of "Pentagon"
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Revision as of 20:39, 14 October 2007
In geometry, a pentagon is a polygon with 5 sides. Each angle of a regular pentagon is . The sum of the internal angles of any pentagon is
.
Construction
It is possible to construct a regular pentagon with compass and straightedge:
http://img164.imageshack.us/img164/1296/pentagonconstructiongt4.png
1. Draw circle (red).
2. Draw diameter and construct a perpendicular radius through
.
3. Construct the midpoint of , and label it
.
4. Draw (green).
5. Construct the angle bisector of , and label its intersection with
as
(pink).
6. Construct a perpendicular to at
.
7. Adjust your compass to length , and mark off points
,
and
on circle
.
8. is a regular pentagon.
See also
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