In geometry, polygons are two-dimensional shapes with straight sides. They can be classified into two main types based on their angles and shape: convex polygons and non-convex polygons.
Convex Polygons :
Definition : A polygon is convex if all its interior angles are less than 180 degrees, and no line segment between any two points on the boundary ever goes outside the polygon.
Features :
All vertices (corners) of the polygon will point outwards.
If you pick any two points within the polygon and draw a line, that line will always lie inside the polygon.
Examples : Regular polygons like equilateral triangles, squares, and regular pentagons are examples of convex polygons.
Properties : Convex polygons tend to be simpler in terms of geometry and calculation. For instance, they always have diagonal lines that lie entirely within the polygon.
Non-Convex Polygons (also known as Concave Polygons) :
Definition : A polygon is non-convex if at least one of its interior angles is greater than 180 degrees.
Features :
At least one vertex (corner) appears to "cave in," or point inwards towards the center of the polygon.
It is possible to draw at least one line between two points on the boundary that passes outside of the polygon.
Examples : A star-shaped polygon or any irregular shape with an indentation is an example of a non-convex polygon.
Properties : Non-convex polygons can be more complex to work with, as calculations involving areas and other properties can be more complicated.
Impact on Shapes and Properties :
The distinction between convex and non-convex affects the geometry and mathematics of the polygon. For example, calculating the area of non-convex polygons can be more challenging because some common methods for computation (like the shoelace formula) assume convex shapes.
Overall, understanding these differences helps in identifying the type of polygon, predicting its behavior in geometrical tasks, and choosing the right approach for solving related problems.