Wolfram Research
Wolfram Math World: Archimedes' Recurrence Formula
This page from Mathworld.com presents illustrations and equations involving Archimedes' Recurrence Formula.
Alabama Learning Exchange
Alex: Discovering Pi
This instructional activity allows learners to discover the number Pi. By measuring real life objects, students will get to see where the number Pi comes from as well as how the circumference formula is derived.This lesson plan was...
University of Cambridge
University of Cambridge: Nrich: Watching the Wheels Go `Round and `Round
Use the formula for the circumference of a circle to solve the challenge of this problem. The solution is available at this one page website.
Cuemath
Cuemath: Area of a Circle
This mini-lesson explores the area of a circle. Provides a definition, examples, and practice questions with answers.
Better Lesson
Better Lesson: Exploring Circumference
What is pi, anyway? Students explore the relationship between circumference and diameter by measuring a variety of circles and use it to derive the formula for circumference.
Math2
Math2: Circles
This site has many useful formulas and examples relating to circles, including related definitions, circumference of a circle, area of a circle, length of a circular arc, area of a circular sector, equation of a circle in cartesian...
CK-12 Foundation
Ck 12: Geometry: Area of a Circle
[Free Registration/Login may be required to access all resource tools.] In this lesson students calculate the area of circles and the area of sectors of circles by using given information and formulas. Students examine guided notes,...
Calculator Soup
Calculator Soup: Sphere Calculator
This online calculator will calculate the 3 unknown values of a sphere given any 1 known variable including radius r, surface area A, volume V and circumference C. It will also give the answers for volume, surface area, and circumference...
Calculator Soup
Calculator Soup: Hemisphere Calculator
This online calculator will calculate the various properties of a hemisphere given any 1 known variable. It also calculates the variables in terms of PI.
Calculator Soup
Calculator Soup: Circular Cylinder Calculator
This online calculator will calculate the various properties of a cylinder given 2 known values. It will also calculate those properties in terms of PI.
ClassFlow
Class Flow: Volume of Cylinders
[Free Registration/Login Required] This flipchart guides the students through the process of determining the volume of a cylinder. Students learn to transform formulas in order to find the missing elements.
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...
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: The Area of a Circle
An investigative approach is given to exploring finding the area of a circle.