CK-12 Foundation
Ck 12: Interactive Geometry: 8.2 Area and Circumference of Circles
A deep dive into the area and circumference of circles.
Mangahigh
Mangahigh: Pyramid Panic: Basic Shapes to Advanced Geometry
Guide a mummy safely through the burial chambers of a pyramid as you solve length and area problems in basic to advanced geometry. There are four game zones that deal with circles and triangles, quadrilaterals, the Pythagorean Theorem,...
Khan Academy
Khan Academy: Radius and Diameter
Practice problems finding radius and diameter of a circle.
Cuemath
Cuemath: Radius
This reference tool explores the radius of a circle. Provides definitions, solved examples, and practice questions with answers.
Varsity Tutors
Varsity Tutors: Hotmath: Practice Problems: Geometry in the Plane
Twenty-four problems presented on a variety of Plane Geometry topics. They are given with each step to the solution cleverly revealed one at a time. You can work each step of the problem then click the "View Solution" button to check...
Curated OER
Circle Picture
This site provides definitions for different parts of a circle, pictures to more clearly represent formulas involving circles. Some of the formulas discussed include: area of a circle, area of a sector of a cirles, circumference, length...
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.
Cool Math
Coolmath: Precalculus Basic Formulas to Know
This CoolMath resource provides an introduction to some Precalculus formulas.
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.
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.
Alabama Learning Exchange
Alex: Geometric Quilts
Students will use a square to investigate other polygonal shapes that can be formed. Students will work with these polygons to make designs that will later constitute cooperatively designed quilts. The quilts will be made by translating,...
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.
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 plan 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.