Illustrative Mathematics
Illustrative Mathematics: 7.g Stained Glass
In this lesson plan, 7th graders use formulas for area and circumference to solve the word problem.
Cuemath
Cuemath: Radius
This reference tool explores the radius of a circle. Provides definitions, solved examples, and practice questions with answers.
Math Open Reference
Math Open Reference: Diameter
A complete reference guide to diameters. It provides definitions, examples, and interactive activities that enhance further explanation. Includes links to related topics.
Khan Academy
Khan Academy: Radius and Diameter
Practice problems finding radius and diameter of a circle.
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...
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
Parametric Unit Circle
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...
Curated OER
Web Math: Find Out Things About Circles
WebMath offers a great site for students to practice finding the diameter, area and circumference of a circle.
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.
PBS
Pbs Learning Media: Formulas: Targeted Math Instruction
At the end of this lesson plan about formulas, students will be able to identify and apply the correct formula for a given situation, solve for any unknown component of the formulas for perimeter, circumference, and area of regular and...
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.
Khan Academy
Khan Academy: Radius and Diameter
Practice finding the radius and diameter of a circle using both vocabulary and visuals. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.
Common Core Sheets
Common Core Sheets: Geometry 8.g.3 Worksheets: Coordinate Plane
Worksheets provide practice with finding the area or circumference of a circle and answer keys are provided. You can even create your own worksheet or flashcards.