Explore everything about circles. Learn various parts of a circle like a diameter, radius, circumference, circles chord, tangent circles, major arc, segment, sector, and discover other interesting aspects of it. Try your hand at solving...

Learn about circles with this handy reference guide. Provides a detailed definition, examples, and interactive activities that enhance further explanation. Includes links to related topics.

Given information about the center and radius of a circle, graph it.

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

This tutorial works through two examples step by step that shows how to complete the square for finding the center and radius of a circle.

Given the standard form equation of a circle, graph the circle.

This site gives a short interactive quiz which allows students to self-assess their understanding of the concept of circle graphs.

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,...

Learn about a line that intersects a circle in two points is called a secant line.

Understand that quadrilaterals that can be inscribed in circles are known as cyclic quadrilaterals.

Basic useful information regarding circles is provided.

This active counting game gets the kids up and moving! Students form a circle and start counting around the circle one by one until the last number (chosen ahead of time by the teacher) in the sequence is reached. When the last number is...

In this activity, students recognize the relationship of angles to circles. They study the Inscribed Angle Theorem and its corollaries.

Scholars explore the Biology concept of life cycles. The tutorial consists of definitions, examples, and pictures. Topics include the great circle dance and life-materials.

This is the full text of the short story "The Adventure of the Red Circle" by Arthur Conan Doyle featuring Sherlock Holmes.

Learn about the segment of a circle with this handy reference guide. Provides detailed definitions and an interactive activity that enhances further explanation. Includes links to related topics.

Find the center and radius of a circle given the equation in expanded form.

Text of the short story "The Magic Circle" by British author Ethel M. Dell. (Free site registration offers some additional features, e.g., the ability to insert annotations.)

A handy reference guide to concentric circles. It provides a definition and an interactive activity that enhances further explanation. Includes links to related topics.

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

Learn how similarity transformation is one or more rigid transformations (reflection, rotation, translation) followed by a dilation.

This lesson plan and related resources are for the book Sarah Bishop by Scott O'Dell, an upper 5th-grade reading level novel about a girl's conflict with the beginnings of the Revolutionary War.

An investigative approach is given to exploring finding the area of a circle.

In this lesson, students learn to inscribe regular polygons inside a circle.