Polygons

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Polygons

• By Beth Roberts

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Polygons

• A polygon is a figure that is made up of only
  line segments. It is a closed figure and its
  sides intersect in exactly two places.
• There are many different polygons this slide
  will look at the triangle, quadrilateral,
  pentagon, hexagon, heptagon, octagon, nonagon and
  decagon.
• There are regular polygons and irregular polygons.

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Regular Polygons

• A regular polygon is a polygon where all sides
  are equal in length and all angles have the same
  measure.
• An equilateral triangle is a regular polygon and
  so is a square.

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Irregular Polygons

• In an irregular polygon, one or more sides do not
  equal the length of the others.

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Triangles

• A triangle is the simplest polygon.
• Triangles only have three sides.
• There are several different types of triangles.
• The sum of the angle measures in a triangle is
  180 degrees.

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Triangles (continued)

• Triangles classified by their sides are the
  isosceles, scalene and equilateral.
• Triangles classified by their angle measure are
  the acute, obtuse and right.

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Triangles (continued)

• Triangle Image

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Quadrilaterals

• A quadrilateral is a four-sided polygon.
• The sum of the angle measures in a quadrilateral
  is 360 degrees.
• There are several different types of
  quadrilaterals.

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Types of Quadrilaterals

• Rectangle any quadrilateral where all four
  angles are right angles.
• Square - a quadrilateral with four equal sides
  that meet at 90 degree angles.
• Parallelogram - a quadrilateral with two sets of
  parallel sides.

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Types of Quadrilaterals (continued)

• Rhombus - a quadrilateral where all four sides
  are of equal length. The difference between a
  square and a rhombus is that in a rhombus, all
  the sides don't need to meet at 90 degree angles.
  
• Trapezoid - a quadrilateral that has exactly one
  pair of parallel sides.

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Images of Quadrilaterals

• Quadrilaterals

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Pentagon

• A pentagon is a five-sided polygon.
• The sum of the angles in a pentagon is 540
  degrees.

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Hexagon

• A hexagon is a six-sided polygon.
• The sum of the angles in a hexagon is 720
  degrees.

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Heptagon

• A heptagon is a seven-sided polygon.
• The sum of the angle measures in a heptagon is
  900 degrees.

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Octagon

• An octagon is an eight-sided figure.
• The sum of the angle measures in an octagon is
  1080 degrees.

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Nonagon

• A nonagon is a nine-sided figure.
• The sum of the angle measures in a nonagon is
  1260 degrees.

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Decagon

• A decagon is a ten-sided figure.
• The sum of the angle measures in a decagon is
  1440 degrees.

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Links to Web Pages for More Information on
Polygons

• Figures and Polygons
• Polygons
• How Many Sides?
• What is a Polygon?

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Further Information

• Polygon Worksheet
• Worksheet Answers
• Back to Polygon Information