About the Book
Please note that the content of this book primarily consists of articles available from Wikipedia or other free sources online. Pages: 87. Chapters: Triangle, Polygon, Quadrilateral, Hexagon, Right triangle, Pentagram, Hexagram, Pseudotriangle, Regular polygon, Pentagon, Stellation, Star polygon, Constructible polygon, Curve orientation, Monotone polygon, Octagon, Five-pointed star, Reuleaux triangle, Four-vertex theorem, Complex polytope, Heptagon, Self-avoiding walk, Pick's theorem, Dodecagon, Orthodiagonal quadrilateral, Heptagram, Net, Equilateral pentagon, Heptadecagon, Simple polygon, Digon, Minimum bounding rectangle, Rectilinear polygon, Apothem, Apeirogon, Dual polygon, Enneagram, Icosagon, Isothetic polygon, Maurer rose, Convex and concave polygons, Complex polygon, List of polygons, polyhedra and polytopes, Unicursal hexagram, Facetting, Golygon, Hendecagon, Hexadecagon, Viviani's theorem, Nonagon, Octadecagon, Polygonal chain, Star-shaped polygon, Tetradecagon, Henagon, Pentadecagon, Equilateral polygon, Nef polygon, Octagram, Triskaidecagon, Hendecagram, Dodecagram, Flag, Enneadecagon, Lemoine hexagon, Visibility polygon, Equiangular polygon, Skew polygon, Dissection problem, Polygon density, Parallelogon, Anthropomorphic polygon. Excerpt: A triangle is one of the basic shapes of geometry: a polygon with three corners or vertices and three sides or edges which are line segments. A triangle with vertices A, B, and C is denoted . In Euclidean geometry any three non-collinear points determine a unique triangle and a unique plane (i.e. a two-dimensional Euclidean space). Euler diagram of types of triangles, using the definition that isosceles triangles have at least 2 equal sides, i.e. equilateral triangles are isosceles. Triangles can be classified according to the relative lengths of their sides: . In diagrams representing triangles (and other geometric figures), "tick" marks along the sides are used to denote sides of equal lengths-- the equilateral ...
