Maths Challenge
Maths challenge.net: Inscribed Rectangle
This is a proof problem, considered a "three star" geometry problem requiring knowledge of proofs and properties of circles to solve this equal area of inscribed polygons problem.
University of Saskatchewan (Canada)
University of Saskatchewan: Geometry
The University of Saskatchewan's Department of Mathematics and Statistics provides high school students with online tutorials and exercises on what they deem some of the most important topics in geometry: Triangles, and Circles and Other...
Maths Challenge
Maths challenge.net: Three Circles
This is a proof problem, considered a "three star" geometry problem requiring knowledge of proofs and properties of circles.
Maths Challenge
Maths challenge.net: Measuring Mountains
Use your triangle solving skills to solve this triangle problem and then apply it to the real world.
Maths Challenge
Maths challenge.net: Maximum Square
A challenging proof like geometry of finding the square inscribed in a triangle.
Maths Challenge
Maths challenge.net: Isosceles Trapezium
This is a "three star" geometry problem where prior knowledge of problem solving and thinking through proofs is recommended to solve this trapezoid inscribed in a semicircle problem.
Maths Challenge
Maths challenge.net: Right Angle Reasoning
A geometry problem for students to use their mathematical reasoning skills to explain a right triangle property.
Maths Challenge
Maths challenge.net: Lunes
A "three star" geometry problem where some experience of math problem solving skills and knowledge of circles is recommended to solve this lunes (parts of a circles) area problem
Oswego City School District
Regents Exam Prep Center: Writing a Proof: Direct Euclidean Proofs
This site is a look into the world of geometric proofs. You'll learn what a proof is and about the different types of proofs. Try the practice page to check your understanding. Teachers can check out the teacher resources for lesson and...
Texas Education Agency
Texas Gateway: Constructing and Justifying Statements About Geometric Figures
Students will distinguish between undefined terms, definitions, postulates, conjectures, and theorems and investigate patterns to make conjectures about geometric relationships.
Cuemath
Cuemath: Euclidean Geometry
Explore the world of Euclidean geometry by understanding euclidean and non-euclidean geometry, the postulates and axioms, and how to apply them while solving problems. Check-out the solved examples for better understanding and try your...
OER Commons
Oer Commons: Mars: Proving the Pythagorean Theorem
This lesson is intended to help you assess how well students are able to produce and evaluate geometrical proofs. PowerPoint slides are included with the lesson.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Two Column Proofs
A response to an inquiry of how to prove a two column geometric proof problem at the Math Forum. This site gives a description of what a makes a proof and an example of a two column proof.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Building Two Column Proofs
Use this site to find details of how to construct a two column proof. Dr. Math responds to a question posed by a student and details the reasons for the order of steps and shows two different ways to do the same proof.
National Council of Teachers of Mathematics
The Math Forum: Ask Dr. Math: Order of a Proof
The site gives a diagram of steps to a proof. Dr. Math explains why the step order of a proof is important.
Texas Instruments
Texas Instruments: Exploring Geometry and Algebra Using Cabri Jr. Application
To prove the Perpendicular Bisectors Theorem using the Cabri Jr. Application, graphically and algebraically.
Texas Instruments
Texas Instruments: Perimeters, Areas, and Slopes Oh, My!
In this activity, students create geometric figures, and use analytic and coordinate geometry to investigate their attributes. They go through the process of proving that a quadrilateral is a parallelogram.
Science Education Resource Center at Carleton College
Serc: Pythagorean Theorem Investigations
In this activity, students will gain an understanding of the Pythagorean theorem and will recognize the variety of ways in which theorems can be proved algebraically, geometrically and visually.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: El Teorema De Pitagoras
Interactive resources and activities that could be used in the classroom either as an introduction or review to a unit dealing with the Pythagoras Theorem. [Requires Java.]
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Relaciones Entre Figuras Geometricas
In Spanish. Explore the world of circle interactively. Some of the topics are circumscribed and inscribed quadrilaterals and point of tangency.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: El Teorema De Pitagoras
In Spanish. In this interactive activity you can learn and understand the concept of the Pythagoras theorem.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: De Los Numeros Naturales a Los Complejos
This interactive unit will expand your knowledge from natural to complex numbers. Learn how to express a complex number in polar form, move from rectangular form to polar form and vice versa, operate with complex in polar form and...
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Coordenadas Polares
Learn how to represent points and curves on the polar coordinate system.
Ministry of Education and Universities of the Region of Murcia (Spain)
Ministerio De Educacion Y Ciencia: Conicas
Learn about the different conic sessions and try the different interactive exercises.