Post on 21-Jan-2015
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Welcome to Welcome to the World the World
of of Polygons!Polygons!
PolygonsPolygons
The word polygon means The word polygon means “many angles”“many angles”
A two dimensional objectA two dimensional object A closed figureA closed figure
More about More about PolygonsPolygons
Made up of three or more Made up of three or more straight line segmentsstraight line segments
There are exactly two sides There are exactly two sides that meet at a vertexthat meet at a vertex
The sides do not cross The sides do not cross each othereach other
Examples of PolygonsExamples of Polygons
These are not These are not PolygonsPolygons
Terms:Terms:
Side: One of the line segments Side: One of the line segments that make up a polygon.that make up a polygon.
Vertex: point where two sides Vertex: point where two sides meet.meet.
Regular Polygon: a polygon Regular Polygon: a polygon where all the angles are where all the angles are equal and all of the sides equal and all of the sides are the same length. They are the same length. They are both equilateral and are both equilateral and equiangularequiangular
Examples of Regular Examples of Regular PolygonsPolygons
Types of Types of PolygonsPolygons
TriangleTriangle A triangle has three sides.A triangle has three sides.
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Everyday triangles…Everyday triangles…
There are There are several types several types of trianglesof triangles
Isosceles Triangles Isosceles Triangles have 2 equal sides.have 2 equal sides.
Equilateral Equilateral Triangles have 3 Triangles have 3 equal sidesequal sides
Scalene Scalene Triangles have Triangles have no equal sidesno equal sides
Acute triangles Acute triangles have 3 acute have 3 acute anglesangles
Obtuse triangles Obtuse triangles have 1 obtuse have 1 obtuse angleangle
Right triangles have Right triangles have 1 right angle1 right angle
Quadrilateral Quadrilateral A quadrilateral has four sides.A quadrilateral has four sides.
SquareSquare
Squares have 4 equal parallel sides Squares have 4 equal parallel sides and 4 right angles.and 4 right angles.
Squares are regular polygonsSquares are regular polygons
Everyday SquaresEveryday Squares
RectanglesRectangles
Rectangles have parallel sides that Rectangles have parallel sides that are equal to each other.are equal to each other.
All angles are right angles.All angles are right angles.
Everyday RectanglesEveryday Rectangles
RhombusRhombus A rhombus has four equal parallel sides.A rhombus has four equal parallel sides.
ParallelogramParallelogram
Parallelograms have opposite equal Parallelograms have opposite equal parallel sidesparallel sides
Everyday ParallelogramsEveryday Parallelograms
TrapezoidTrapezoid
Trapezoids have one set of Trapezoids have one set of parallel sides.parallel sides.
Everyday TrapezoidsEveryday Trapezoids
PentagonPentagon A pentagon has five sides.A pentagon has five sides.
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Everyday PentagonsEveryday Pentagons
Hexagon Hexagon
A hexagon has six sides. (Hexagon A hexagon has six sides. (Hexagon and six both have an “x”.)and six both have an “x”.)
Everyday HexagonsEveryday Hexagons
HeptagonHeptagon
A heptagon has seven sides.A heptagon has seven sides.
Everyday HeptagonsEveryday Heptagons
OctagonOctagon
An octagon has eight sides. Count An octagon has eight sides. Count the sides.the sides.
If this octagon was red and had the word “Stop” written on it, then you would know where we see a lot of octagons.
Everyday OctagonsEveryday Octagons
NonagonsNonagons
Nonagons have nine sidesNonagons have nine sides
Everyday NonagonsEveryday Nonagons
DecagonDecagon Decagons have 10 sides.Decagons have 10 sides.
Everyday DecagonsEveryday Decagons
HendecagonHendecagon
Hendecagons have 11 Hendecagons have 11 sidessides
Everyday HendecagonsEveryday Hendecagons
DodecagonsDodecagons
Dodecagons have 12 sidesDodecagons have 12 sides
Everyday DodecagonsEveryday Dodecagons
A triangle is the smallest polygon because it has three sides. Can you have a two-sided polygon? Why or why not?
Two lines don’t close to make a shape. They make an angle.
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Key Question:Key Question: