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POLYGONSUnderstanding the properties of various shapes,or figures, is going to be key throughoutGeometry.In this lesson, we will explore some of theseshapes, more formerly known as polygons. Sara Reyes CSE 684 Spring 2012
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LEARNING OBJECTIVESFirst, to distinguish betweenconvex and concave polygons. Next, to distinguish between regular and irregular polygons. Lastly, to classify polygons according to how many sides they have.
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WHAT ARE POLYGONS?Closed shapes or figures in a plane with three or moresides.Alternatively, a polygon can be defined as a closedplanar figure that is the union of a finite number of linesegments.The term polygon is derived from a Greek wordmeaning “many-angled”.
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CONVEX VS. CONCAVE POLYGONSConvex polygon- A Concave polygon- Apolygon for which any two polygon that is not convex. Ainterior points can be line segment connecting twoconnected by a line segment points may pass outside thethat stays entirely inside the figure.polygon.
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WHAT HAVE WE COVERED SO FAR? Distinguish between convex and concave polygons Distinguish between regular and irregular polygons Classify polygons according to the number of sides they haveo classify polygons according to how many they have
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REGULAR VS. IRREGULAR POLYGONS An irregular polygon is a polygon whose sides are notA regular polygon is a the same length or whosepolygon in which all the interior angles do not allangles and sides are equal. have the same measure.
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SO, WHAT HAVE WE COVERED SO FAR? Distinguish between convex and concave polygons Distinguish between regular and irregular polygons Classify polygons according to the number of sides they haveo classify polygons according to how many they have
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WHAT IS A TRIANGLE?A triangle, sometimes called a trigon, is a three-sided polygon.
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WHAT IS A QUADRILATERAL?A quadrilateral is a four-sided polygon.
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WHAT IS A PENTAGON?A pentagon is a five-sided polygon.
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WHAT IS A HEXAGON?A hexagon, also referred to as a sexagon, is a six-sided polygon.
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WHAT IS A HEPTAGON?A heptagon, also referred to as a septagon, is a seven-sided polygon.
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WHAT IS A OCTAGON?An octagon is a eight-sided polygon.
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WHAT IS A NONAGON?A nonagon is a nine-sided polygon.
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WHAT IS A DECAGON?A decagon is a ten-sided polygon.
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SO, WHAT HAVE WE COVERED SO FAR? Distinguish between convex and concave polygons Distinguish between regular and irregular polygons Classify polygons according to the number of sides they haveo classify polygons according to how many they have Lets recap what we learned throughout this lesson…
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RECAP OF WHAT WE LEARNED… A polygon is a closed figure with three (or more) sides. When any two interior points of a polygon are connected by a line segment that: stays entirely inside, it is a convex polygon passes outside, it is a concave (“caved in”) polygon Regular polygons have equal side lengths and equal interior angle measures whereas irregular polygons do not. Polygons can be classified by the number of sides: three-sided = triangle four-sided = quadrilateral five-sided = pentagon etc.
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