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Geometry in Two Dimensions
This note is intended for students who have a background in multivariable calculus and some experience in proof-based mathematics. Topics covered includes: Euclidean geometry, Polygons, Triangulations and Tilings, The Chord Theorem, Tangrams and Scissors Congruence, Spherical Geometry, Hyperbolic geometry, Euclids axioms and the parallel postulate, Incidence geometry and Hyperbolic isometries.
Author(s): Ian Biringer
133 Pages 
Foundations of Geometry by David Hilbert
This PDF book covers the following topics related to Geometry : The Five Groups of Axioms, the Compatibility and Mutual Independence of the Axioms, the Theory of Proportion, the Theory of Plane Areas, Desargues’s Theorem, Pascal’s Theorem, Geometrical Constructions Based Upon the Axioms I-V.
Author(s): David Hilbert, Ph. D. Professor of Mathematics, University of Göttingen
105 Pages
This PDF book covers the following topics related to Geometry : Introduction, Construction of the Euclidean plane, Transformations, Tricks of the trade, Concurrence and collinearity, Circular reasoning, Triangle trivia, Quadrilaterals, Geometric inequalities, Inversive and hyperbolic geometry, Projective geometry.
Author(s): Kiran S. Kedlaya
142 Pages
This text is intended for a brief introductory course in plane geometry. It covers the topics from elementary geometry that are most likely to be required for more advanced mathematics courses. Topics covered includes: Lines Angles and Triangles, m Congruent Triangles, Quadrilaterals, Similar Triangles, Trigonometry of The Right Triangle, Area and Perimeter, Regular Polygons and Circles, Values of The Trigonometric Functions.
Author(s): Henry Africk
NA Pages
This note is a branch of mathematics concerned with questions of shape, size, relative position of figures, and the properties of space.
Author(s): Acellus School
147 Pages
Euclidean Geometry by Rich Cochrane and Andrew McGettigan
This is a great mathematics book cover the following topics: Equilateral Triangle, Perpendicular Bisector, Angle Bisector, Angle Made by Lines, The Regular Hexagon, Addition and Subtraction of Lengths, Addition and Subtraction of Angles, Perpendicular Lines, Parallel Lines and Angles, Constructing Parallel Lines, Squares and Other Parallelograms, Division of a Line Segment into Several Parts, Thales' Theorem, Making Sense of Area, The Idea of a Tiling, Euclidean and Related Tilings, Islamic Tilings.
Author(s): Rich Cochrane and Andrew McGettigan
102 Pages
Topics in Geometry Dirac Geometry Lecture Notes
This is an introductory note in generalized geometry, with a special emphasis on Dirac geometry, as developed by Courant, Weinstein, and Severa, as well as generalized complex geometry, as introduced by Hitchin. Dirac geometry is based on the idea of unifying the geometry of a Poisson structure with that of a closed 2-form, whereas generalized complex geometry unifies complex and symplectic geometry.
Author(s): Prof. Marco Gualtieri
NA Pages