A polygon is a closed figure formed by line segments. At least three line segments are needed to form a polygon.
Kinds of Polygons:
No. of Sides
|
Polygons
|
3
4
5
6
7
8
9
10
11
12
|
Triangle
Quadrilateral
Pentagon
Hexagon
Heptagon
Octagon
Nonagon
Decagon
Undecagon
Dodecagon
|
TRIANGLE is a polygon of 3 sides.
Kinds:
1. Scalene triangle has no two sides congruent or the measure of the sides are not equal.![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEidjHEy5ULxGfVvMvi2jVtaMN7bd22FcrU4rIXYw_dUAqBghHLbq0dzqDR86_15w-aIH-3vlJqLkewxx-La5zAw4kqnFtskJnp7RybKTibV8rtA7kZWov0gXbkTXlWNLFbsvq91Oq9UmDAx/s200/scalene.gif)
2. Isosceles triangle has 2 congruent sides or the measures of two sides are equal.
![](http://www.k6-geometric-shapes.com/image-files/triangle-isosceles.jpg)
![](http://www.k6-geometric-shapes.com/image-files/triangle-equilateral.jpg)
QUADRILATERAL is a polygon of four sides.
QUADRI means 4 lateral sides.
Kinds:
1. Parallelogram has 2 pairs of parallel sides and opposite sides are congruent. It has length and width with one pair of obtuse angles and one pair of acute angles.
![](http://www.wyzant.com/Help/Images/parallelogram1.gif)
2. Rectangle has length and width. The opposite sides are congruent and has 4 right angles and 2 pairs of parallel sides.
![](http://www.mathsisfun.com/images/quadrilateral-rectangle.gif)
3. Square has 4 congruent sides and 4 congruent angles. It has 2 pairs of parallel sides.
![](http://www.shmoop.com/images/prealgebra/unit4/pa.4.156.png)
4. Rhombus has 4 congruent sides, 2 pairs of parallel sides, 1 pair of obtuse angle and 1 pair of acute angle.
![](http://www.ams.org/featurecolumn/images/barcodes61.jpg)
5. Trapezoid has 1 pair of parallel sides.
![](http://www.k6-geometric-shapes.com/image-files/quadrilateral-trapezoid.jpg)
In isosceles trapezoid the non-parallel sides are congruent.
![](http://www.k6-geometric-shapes.com/image-files/quadrilateral-isosceles-trapezoid.jpg)
6. Trapezium has no pair of parallel sides.
![](http://etc.usf.edu/clipart/38600/38613/trapezium_38613_sm.gif)