Euclidean Geometry
AoPS Faculty
Master Euclidean Geometry with AoPS Faculty! This course covers proofs, theorems, and problem-solving techniques.
More resources on Euclidean Geometry
Wolfram MathWorld
MathWorld is an online mathematics encyclopedia from Wolfram Research offering detailed, browsable articles on topics across the math spectrum, including algebra, geometry, calculus, and number theory. Each entry includes definitions, theorems, formulas, diagrams, worked examples, and links to further reading.
Geometry
Classic Houghton Mifflin/McDougal Littell high-school geometry textbook built around two-column proofs. Works through congruent triangles, parallel lines, similarity, circles, area, volume, coordinate geometry and transformations, with graded exercises that train students to write rigorous Euclidean proofs.
Euclidean and Non-Euclidean Geometries
Marvin Jay Greenberg's university text on the foundations of geometry. Rebuilds Euclidean geometry from Hilbert's axioms, traces the history of attempts to prove the parallel postulate, then develops hyperbolic geometry and its models, so readers understand what Euclid's axioms do and don't imply.
mathsisfun.com
MathIsFun.com is a beginner-friendly math site that explains concepts with clear, step-by-step lessons and interactive activities. It covers topics from algebra and linear equations to geometry, fractions, data, and more, with practice problems, worksheets, and quizzes.
Geometry: A Comprehensive Course
Dan Pedoe's Dover text treating geometry through vectors and linear algebra. Covers circles, inversion, the Euclidean and affine plane, projective geometry, conics and quadrics, giving readers with some algebra a unified, coordinate-based view of classical Euclidean results.