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A curve - Take a pencil and piece of paper and draw a path without lifting the pencil from the paper or retracing any part of the path, except to cross it. |  |
A polygonal curve - A curve that is entirely made up of line segments. (no arcs) |
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A closed curve - A curve that begins and ends in the same location. |  |
A polygonal closed curve - A polygon curve that begins and ends in the same location. |
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A simple closed curve - A closed curve that does not cross itself. |  |
A simple polygonal closed curve - A polygon closed curve that does not cross itself. |
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How would you describe me? |  |
How would you describe me? (other than circle!!) |
Polygons ("many angles") - All polygons are simple, closed polygonal curves.
The line segments that form a polygon are called the sides of the polygon. A point where two sides meet is a vertex (plural form is vertices). Any two sides determine an interior angle of the polygon; an exterior angle is formed by a side and an adjacent side extended.
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Given Polygon ABCD then its: Sides are AB, BC, CD, CE, and EA. Vertices are A, B, C, D, and E. Interior angles: ex. angle BCD (green angle) Exterior angles: ex. angle EDJ (yellow angle) |
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There are three parts to a polygon: the interior (green region), the exterior (yellow region), and the polygon itself (black region). The polygon and its interior make up a polygonal region. |
| A convex polygon can be determined using the following property: A line segment joining any two points inside the figure lies completely inside the figure. A non convex polygon is called a concave polygon. One way to remember this is to think of concave polygons being like caves. |  |
List the numerical values of the shapes that are convex __________________
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One way to classify polygons is by the number of sides they have. When a polygon is equiangular (all angles are equal) and equilateral (all sides are equal) we say that it is regular. Regular polygons that we are familar with would be the equilateral triangle or the square.
| Number of Sides(n) |
Polygon Name | Diagram | Regular Polygon Name | Diagram |
| 3 | Triangle |  |
Equilateral |  |
| 4 | Quadrilateral |  |
Square |  |
| 5 | Pentagon |  |
Regular Pentagon |  |
| 6 | Hexagon |  |
Regular Hexagon |
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| 7 | Heptagon | etc.. | Regular Heptagon |
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| 8 | Octagon | etc.. | Regular Octagon |
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| 9 | Nonagon | etc... | Regular Nonagon |
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| 10 | Dodecagon | etc.. | Regular Dodecagon |
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| n - gon | n - gon | etc... | Regular n - gon |
etc... |
Puzzle #1. Tangrams