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.
Ministerio de Educacion, Cultura y Deporte (Spain)
Cnice: Relacion De Ejercicios Interactivos.
In Spanish. Interactive activities online on various geometric and trigonometric concepts such as area, perimeter, secants, tangents, etc. A terrific resource for students. Site is organized acoording to shape. (triangle, quadrilaterals,...
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.
Khan Academy
Khan Academy: Radius and Diameter
Practice problems finding radius and diameter of a circle.
Annenberg Foundation
Annenberg Learner: Math in Daily Life: Home Decorating
This exhibit is designed to show students that geometry really does apply to the real world. By taking viewers through a home decoration project, students learn how to calculate area of a rectangle and circle.
Vernet -Virtual Education Resources Network
Salon Hogar: Referencia Rapida De Formulas Geometricas
This site provides the user with a useful reference to different geometric forms, their elements, formulas, and areas. Entirely in Spanish.
Analyze Math
Analyze Math: Polygons Problems
Here are four problems about the area of a regular polygon. Start by finding the area of a hexagon inscribed in a circle of radius 10, and end by proving that as the number of sides of the polygon increases, the area of the polygon...
Cuemath
Cuemath: Radius
This reference tool explores the radius of a circle. Provides definitions, solved examples, and practice questions with answers.
Cool Math
Coolmath: Precalculus Basic Formulas to Know
This CoolMath resource provides an introduction to some Precalculus formulas.
Other
Allmath: Math Glossary
Are your students having difficulty understanding math terminology? Try this A-Z glossary on math related terms. It's quick, easy to read, and very complete.
Calculator Soup
Calculator Soup: Annulus Calculator
This online calculator will find the area, circumference, and radii of an annulus. With any 2 known variables, you can calculate the other 5 unknowns.
University of St. Andrews (UK)
University of St. Andrews: James Gregory
This site, which is provided for by the University of St. Andrews, contains information on the mathematician Gregory and his accomplishments.
Math2
Math2
This is a site for students and teachers of all grade levels. If you are looking for math tables, general information about math topics, or you would like to ask a question, this is the site to visit.
Mr. Martini's Classroom
Mr. Martini's Classroom: Teacher's Figure Library: Geometric Figures
This interactive resource provides an example picture of the geometric figure chosen by students to review.
Khan Academy
Khan Academy: Circumference and Rotations
Practice these problems with circumference and rotations.
Calculator Soup
Calculator Soup: Volume Calculator
Use this online calculator to calculate the volume of geometric solids including a capsule, cone, frustum, cube, cylinder, hemisphere, pyramid, rectangular prism, sphere, and spherical cap.
National Council of Teachers of Mathematics
The Math Forum: Multicultural Math Fair: Srinivasa's Spheres
Straightforward lesson that introduces learners to pi by letting them measure real objects and solve a challenge problem. Includes instructions and a "Data Sheet" for keeping track of measurements. Available in English and Spanish.