This study guide on circumference and arc length covers key vocabulary, the parts of a circle, and formulas for circumference, area, and arc length. It is available for download with free registration.

This mini-lesson explores the area of a circle. Provides a definition, examples, and practice questions with answers.

Practice interesting area and circumference problems. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

The Math Forum offers an archive of question and answer sessions on circles and how they relate to geometry.

Find the circumference of a circle when given either the radius or diameter.Find the radius or diameter of a circle when given the circumference.Students receive immediate feedback and have the opportunity to try questions repeatedly,...

A complete reference guide to the area enclosed by a circle. It provides definitions, examples, and an interactive activity that enhances further explanation. Includes links to related topics.

Use this circle calculator to find the area, circumference, radius, or diameter of a circle. Given any one variable A, C, r or d of a circle you can calculate the other three unknowns.

This tutorial will show you how using formulas can help you solve problems. Include formulas for various geometric shapes and steps showing how to use them.

This CoolMath resource provides an introduction to some Precalculus formulas.

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.