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: Annulus
An annulus of a circle is defined and then a proof like problem is posed involving area and radius of circles.
Maths Challenge
Maths challenge.net: Semi Circle Lunes
A lune of a circle is defined and a problem of finding the area of two lunes is given.
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: Rectangular Circles
An area problem involving finding the area of a rectangle and a circle. The problem may be made into a general proof as well.
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
Science Education Resource Center at Carleton College
Serc: Pythagorean Theorem Investigations
In this activity, learners 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.
Maths Challenge
Maths challenge.net: Quadrilateral Parallelogram
A "three star geometry problem" requiring knowledge of how to complete geometric proofs and some prior math knowledge. This problem asks to prove that the mid points of any quadrilateral form a parallelogram.
Maths Challenge
Maths challenge.net: Unique Circle Equal Angles
A "three star geometry problem" - requiring the knowledge of biconditional statements and how to prove such problems.
Maths Challenge
Maths challenge.net: Odd Vertices
A "three star geometry problem" requiring knowledge of how to complete geometric proofs. The problem explains what the order of a vertex is and asks for the proof of a generalization.
Maths Challenge
Maths challenge.net: Coloured Strings
A "three star geometry problem" - requiring the knowledge of what a cuboid is and a some knowledge of how to do proofs.
Maths Challenge
Maths challenge.net: Parallelogram Property
A "three star geometry problem" requiring knowledge of how to complete geometric proofs properties of parallelogram.
Maths Challenge
Maths challenge.net: Platonic Solids
A "three star geometry problem" requiring knowledge of how to complete geometric proofs to prove that there are no more than five regular convex polyhedra.
Maths Challenge
Maths challenge.net: Tiled Floor
An area problem involving diagonals of a tiled floor.
Maths Challenge
Maths challenge.net: Shaded Square
A problem of finding the fraction of a square that is shaded given criterion. Students will have to use their mathematical reasoning and triangle solving skills to solve this area problem.
Maths Challenge
Maths challenge.net: Shaded Hexagon
A problem with equilateral triangles and area to solve this "Shaded Hexagon" problem. Mathematical reasoning and triangle knowledge will be needed to solve the problem.
Maths Challenge
Maths challenge.net: Peculiar Perimeter
This is a "three star" geometry problem where prior math problem skills and proof experience is recommended. Tile constructions may be used to solve this perimeter and area problem.
Maths Challenge
Maths challenge.net: Corner Circle
This is a "three star" geometry problem where prior knowledge of circles and triangles is recommended to solve this circle in the corner problem.
Maths Challenge
Maths challenge.net: Curvature of the Earth
Distance problem using a spherical radius and height.
Maths Challenge
Maths challenge.net: Shaded Cross
Find the area of this tilted cross with your geometry skills.
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).
Shodor Education Foundation
Shodor Interactivate: Squaring the Triangle
Learn about how the Pythagorean Theorem works through investigating the standard geometric proof.
CK-12 Foundation
Ck 12: Interactive Geometry: 1.7 the Pythagorean Theorem
Explore and discover the Pythagorean theorem.