Types of Polygons: Triangles, Quadrilaterals, Pentagons, Hexagons, and Heptagons

Study Notes

Polygons are geometric figures composed of straight lines connected end-to-end to form closed shapes. They come in various forms, each with unique properties and characteristics. Here's what you need to know about the different types of polygons:

Triangle: A triangle is a three-sided figure formed by connecting three noncollinear points. There are several types of triangles based on their side lengths: equilateral (all sides equal), isosceles (two sides equal), and scalene (no sides equal). Triangles can also be classified into types such as obtuse (one angle larger than 90°) and acute (all angles smaller than 90°).
Quadrilateral: A quadrilateral is a four-sided figure with all interior angles less than 180°. Examples include squares, rectangles, parallelograms, and trapezoids. These polygons have properties like opposite sides being congruent with respect to parallel sides, diagonals bisecting the interior angles, and alternate interior angles being congruent.
Pentagon: A pentagon is a five-sided irregular polygon. Regular pentagons have all sides equal and all angles equal, while irregular ones do not. Pentagons can also be classified according to their degree of symmetry, which ranges from regular (symmetrical along five axes of rotation) to highly asymmetric. Some famous examples of pentagons include the dodecahedron, which is one of the five Platonic solids.
Hexagon: A hexagon is a six-sided figure. Regular hexagons have all sides equal and all angles equal to 120°. There are three types of regular hexagons based on their symmetry: rectangular (two axes), trigonal (three axes), and square (four axes). Hexagonal prisms and pyramids are examples of polygonal shapes that can be formed using hexagons as bases.
Heptagon: A heptagon is a seven-sided polygon. Similar to other polygons, there are both regular and irregular versions of heptagons. Regular heptagons have all sides equal and interior angles measuring 128.571428571 degrees each. Some geometric structures made up of heptagons include the Schönhardt polyhedron and the Coxeter-Dynkin diagram for E7.

As you explore these different types of polygons, remember that they form the foundation for understanding more complex geometric shapes like polyhedra and higher-dimensional objects.

Description

Learn about different types of polygons, including triangles, quadrilaterals, pentagons, hexagons, and heptagons. Discover their unique properties, classifications based on symmetry and side lengths, and famous examples like the dodecahedron. Expand your knowledge of foundational geometric shapes.