1. A Presentation On Polygon
Submitted by-
Tarni Agarwal (K-1489)
Class -VII C
Mayo College Girls’ School, Ajmer

2. POLYGONS A polygon is a plane shape with straight sides
POLYGONS A polygon is a plane shape with straight sides. It is a closed plane figure made up of several line segments that are joined together. The sides do not cross each other. Exactly two sides meet at every vertex.
Polygons are 2-dimensional shapes. They are made of straight lines, and the shape is "closed" (all the lines connect up).
Polygon  (straight sides)
Not a Polygon  (has a curve)
Not a Polygon  (open, not closed)
Polygon comes from Greek. Poly- means "many" and -gon means "angle".

3. Types of Polygon Simple or Complex
A simple polygon has only one boundary, and it doesn't cross over itself. A complex polygon intersects itself! Many rules about polygons don't work when it is complex.
Simple Polygon (this one's a Pentagon)
Complex Polygon (also a Pentagon)

4. Concave or Convex
A convex polygon has no angles pointing inwards. More precisely, no internal angles can be more than 180°.
If there are any internal angles greater than 180° then it is concave. (Think: concave has a "cave" in it)
Convex
Concave

5. Regular or Irregular
If all angles are equal and all sides are equal, then it is regular, otherwise it is irregular
Regular polygons are both equiangular and equilateral. Equiangular - all angles are equal. Equilateral - all sides are the same length.
Regular
Irregular

6. Polygon parts
Side - one of the line segments that make up the polygon.
Vertex - point where two sides meet. Two or more of these points are called vertices.
Diagonal - a line connecting two vertices that isn't a side.
Interior Angle - Angle formed by two adjacent sides inside the polygon.
Exterior Angle - Angle formed by two adjacent sides outside the polygon.

7. Name of Polygons (If it is a regular Polygon)
Name Sides Shapes Interior Angle
Triangle (or Trigon) o
Quadrilateral (or Tetragon) o
Pentagon o
Hexagon o
Heptagon (or Septagon) o
Octagon o
Nonagon (or Enneagon) o
Decagon o

8. Complex Polygon (a "star polygon", in this case, a pentagram)
More Examples:
Complex Polygon  (a "star polygon", in  this case, a pentagram)
Concave Octagon
Irregular Hexagon