McGraw Hill
Glencoe Mathematics: Self Check Quiz on Reasoning & Proof
The online assessment demonstrates knowledge of concepts utilized in Geometry. The multiple choice questions test students on mathematical reasoning and proof.
Oswego City School District
Regents Exam Prep Center: Styles of Proof
Find out the general form for two column proofs, flow proofs, and paragraph proofs here. The site is very brief and discusses each type of proof using the same example.
Analyze Math
Analyze Math: Inscribed and Central Angles in Circles
The geometry tutorial investigates the definitions and theorems related to inscribed and central angles in circles. An example with a detailed solution is included.
Illustrative Mathematics
Illustrative Mathematics: G C Similar Circles
For this task, students are asked to show that all circles are similar using two different methods, a visual one and an algebraic one. Includes a GeoGebra worksheet that can be used by the instructor to demonstrate the material. Aligns...
Mathigon
Mathigon: Euclidean Geometry: Euclid's Axioms
This lesson focuses on Euclid's Axioms, simple, intuitive statements, that everyone agrees are true. An axiom(or postulate) is a mathematical statement that is regarded as "self-evident" and accepted without proof. A key part of...
Math Open Reference
Math Open Reference: Congruence
A complete reference guide to congruence including congruent triangles and polygons. It provides definitions, animation, and interactive activities that enhance further explanation.
Math Planet
Math Planet: Geometry: Proofs Using Algebra
Examples and a video lesson help to explain proofs and logic. [1:57]
Math Planet
Math Planet: Geometry: Working With Logic
How to determine if a logical statement is true or false is explained through examples and a video lesson. [2:46]
Math Planet
Math Planet: Geometry: Conjecture
Conjecture is explained through examples and a video lesson. [0:41]
CK-12 Foundation
Ck 12: Geometry: Indirect Proof in Algebra and Geometry
[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to write an indirect proof and provides examples of indirect proofs in Algebra and Geometry.
CK-12 Foundation
Ck 12: Geometry: Indirect Proof in Algebra and Geometry
[Free Registration/Login may be required to access all resource tools.] Write algebraic and geometric indirect proofs.
Rice University
Rice University: Cynthia Lanius: History of Geometry
Different cultures' contributions to Geometry are discussed.
CK-12 Foundation
Ck 12: Geometry: Proofs Study Guide
[Free Registration/Login may be required to access all resource tools.] This study guide reviews proofs: algebraic proof, properties of congruence, and geometric proofs (two-column).
Alabama Learning Exchange
Alex: Geometrica Fights Back!
This activity is designed to give students practice with the properties of special quadrilaterals (parallelograms, rectangles, rhombuses, squares, trapezoids, and kites). The students are provided with a "murder mystery" sheet with...
CK-12 Foundation
Ck 12: Geometry: Basics of Geometry Study Guide
This study guide on Geometry covers some key vocabulary, drawing and labeling diagrams, describing geometric figures, and basic postulates for points, lines, planes, and intersections. It is available for download with free registration.
Geometry Help
Geometry Help: Inscribed Shapes
Explains the basic concept of inscribed shapes with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
Geometry Help
Geometry Help: Circles
Explains the basic concept of circles with step-by-step instructions and methods for solving specific problems on your own relating to this topic.
National Council of Teachers of Mathematics
Nctm: Illuminations: A Geometric Investigation of (A + B)2
This interactive demonstrates why (a + b)2 = a2 +2ab + b2.
Math Open Reference
Math Open Reference: Incircle
A complete reference guide to incircles. It provides definitions and examples that enhance further explanation. Includes links to related topics.
CK-12 Foundation
Ck 12: Interactive Geometry: 10.2 Equations of Circles
Derive the equation of a circle with the help of the Pythagorean Theorem.
CK-12 Foundation
Ck 12: Interactive Geometry: 4.1 Theorems and Proofs
Understand theorems and proofs as they relate to geometry.
National Council of Teachers of Mathematics
Nctm: Illuminations: Proof Without Words: Completing the Square
Use this interactive geometric proof to complete the square using geometry.
Dartmouth College
Dartmouth College: The Different Styles of Euclid and Copernicus
A history of the differences between Euclid's and Copernicus's methods of proving geometric ideas.
National Council of Teachers of Mathematics
The Math Forum: Conic Sections/circles
This site provides a catalog of Web sites and Web pages that deal with circles.