Curated OER
Euclidean Direct Proofs
Learning how to prove theorems in geometry can be challenging. This resource explains what a proof is, and the different styles for proofs. It also contains links to web-based practice problems that help guide learners though example...
University of California
Euclidean Geometry
Go back to where it all began! Investigate how axiomatic systems and Euclidean geometry are based on undefined terms, common notions, postulates, and propositions by examining passages from Euclid's Elements. (Social studies teachers...
Curated OER
NON-EUCLIDEAN GEOMETRY.
Young scholars study relationships between angles, side lengths, perimeters, areas and volumes of similar objects. In this lesson students also create and critique inductive and deductive arguments concerning congruency, similarity and...
Curated OER
Euclidean Algorithm
Learners are introduced to the concept of a Greatest Common Divisor. They review the number systems. Students are told how the entire field of Number Theory primarily uses the integers. They are told the Fundamental Theorem of Algebra.
Massachusetts Department of Education
Similarity through Transformations
Create the ultimate miniature golf course. The 93-page model curriculum unit from the Massachusetts Department of Elementary and Secondary Education contains nine lessons on understanding similarity in terms of both Euclidean geometry...
Curated OER
Investigating the Sierpinski Triangle
Students solve and analyze the sierpinski's triangle. In this geometry lesson, students identify properties and theorem of triangles. They solve problems involving angles and sides of triangles.
Curated OER
Preparation and Transition to Two-Column Proofs
Students investigate proofs used to solve geometric problems. For this geometry lesson, students read about the history behind early geometry and learn how to write proofs correctly using two columns. The define terminology valuable to...
Curated OER
The Flat Earth
Students differentiate between different planes. In this geometry lesson, students differentiate between a plane and a sphere. They discuss the Great Circle, Geodesic and Lune as it relates to the earth.
Oswego City School District
Regents Exam Prep Center: Theorems and Postulates for Geometry
Here is a partial list of theorems, postulates, and properties.
Other
Georgia Tech: The Four Color Theorem
An explanation and proof of the Four Color Map Theorem. Includes illustrative images and a plethora of information.
Cut the Knot
Cut the Knot!: Analogues and Generalization of the Pythagorean Theorem
This site discusses the theorems and other findings which are directly related to the fundamental Pythagorean theorem. Be sure to click on the link to information on Pythagorean theorem to find several proofs of the theorem.
Other
Mathematical the Four Color Theorem and Computer Proof
This site describes the role of computer involvement in the four color map theorem.
Wolfram Research
Wolfram Math World: Distance
MathWorld.com gives a formula for finding distance using the Pythagorean theorem. The formula for finding the distance between two points in Euclidean space is given on this page. The page has links to related topics.
University of St. Andrews (UK)
University of St. Andrews: St. Andrews: History of the Four Color Theorem
The University of St. Andrews offers a brief history of the first math problem to be solved with computers.
Oswego City School District
Regents Exam Prep Center: Lines and Planes
Use these resources in preparing instruction on undefined terms (points, lines, and planes), theorems relating lines and planes, and Euclidean and non-Euclidean geometry. You'll find three lessons on the aforementioned subject areas, an...
Wolfram Research
Wolfram Math World: Geometry
This MathWorld tutorial provides detailed overviews of the concepts and theorems associated with geometry. Most of the Math World sites are extensive and some require higher math knowledge to understand, links to terms and topics are...
Cut the Knot
Cut the Knot!: Interactive Mathematics: Geometry Articles, Theorems, Problems
Contains over five hundred Geometry articles, problems, puzzles, and games. Some sites relating to circles are provided within this list.
Cut the Knot
Cut the Knot!: The Law of Cosines (Cosine Rule)
This site from Cut The Knot provides an overview of the law of cosines, complete with an explanation of the law and a proof of the law.