POLYGONS
What is polygon?
-  A polygon is any flat shape with tree or more sides. Polygons are closed figure which means that the lines are closed and not open.

-Alternatively, a polygon can be defined as a closed planar figure that is the union of a finite number of line segments.The term polygon is derived from a Greek word meaning “many-angled”.

-A polygon: Formed by 3 or more segments (sides), no two sides with common endpoints are collinear Each side intersects exactly 2 other sides, one at each end point Endpoints are called a Vertex (vertices).
What are the types of polygons?
Convex and concave
Polygons first fit into two general categories— convex and not convex (sometimes called concave). A polygon is concave if there are two points somewhere inside it for which a segment with these as its endpoints cuts at least 2 of the sides of the polygon. A polygon that is not concave is called convex

Regular polygons

Regular Polygons A regular polygon is a polygon whose sides are all the same length, and whose angles are all the same. The sum of the angles of a polygon with n sides, where n is 3 or more, is 180° × (n - 2) degrees.

Polygons Types and Using Daily Life

Triangle
3 sided polygon.

A triangle is a polygon with  three vertices or corners, and TRIANGLE three edges. There are three main types of  triangles an obtuse, acute, and right. An obtuse triangle has one obtuse angle meaning the angle has a degree measure larger then 90 degrees. An acute triangle has three acute angles meaning the angles have a degree measure less than 90 degrees. A right triangle has one right angle meaning the angle has a degree measure of 90 degree.
To find the perimeter of the triangle edges are collected. =a+b+c
The area is; 

According to sides and angles are varieties.

Using in daily life

Square (Quadrilateral) 
4 sided polygon

A quadrilateral is a  polygon with four vertices or corners, and four edges. There are many different types of quadrilaterals. The  most recognized are squares and rectangles. A square is a rectangle with four edges of the same length and four 90 degree right angles. A rectangle is a four sided quadrilateral with four 90 degree right angles.
The environmental of square: a*4
The area of square a^2=a*a

Using in daily life

Pentagon
5 sided polygon.

A pentagon is any five sided polygon. The most commonly know pentagon would be the Pentagon building. This is a building with five equal sides in length.
Environment of pentagon

Using in daily life

Hexagon

6 sided polygon.

A hexagon is a polygon with six vertices or corners and  six edges.  A beehive has hexagonal shaped honeycombs, in order to ensure that there are no gaps between any of the honeycombs

Using in daily life

Heptagon
7 sided polygon.

A heptagon is a polygon with seven angles and  seven sides. A regular heptagon has seven equal sides and seven equal angles

Using daily life

Octagon

8 sided polygon.

An octagon is a polygon with eight sides.  The most common octagon is the stop sign

Using daily life

Common features

Sum of all angle measures in an n - gon: ( n – 2) • 180º Angle Measures in a Polygon In the activity, you used triangles to find the sum of the angle measures in polygons. In a regular polygon, the measure of one angle is the sum of the angle measures divided by the number of sides. n = number of sides of the polygon  Polygons and Angles  . Measure of one angle in a regular n -gon: ( n – 2) • 180º n

You can watch the video for polygons.

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