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...

This problem examines equations defining different circles in the x-y plane. Students must use the Pythagorean Theorem to find equations whose solutions are points on the circle and explain why they work. Includes a GeoGebra worksheet...

Given the standard form equation of a circle, graph the circle. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Given the expanded equation of a circle, graph the circle. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or receive hints.

Detailed math tutorial features notes and examples that illustrate graphing circles.

This site from the University of Saint Andrews shows the involute of a circle graphically and gives brief history. Cartesian equation is given.

In this activity, students can use the Cabri Jr. application to explore circles in a plane. They will investigate the relationship between the equation of a circle, the length of its radius, and the coordinates of its center. [Requires...

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.

[Free Registration/Login may be required to access all resource tools.] This concept teaches students how to graph circles and find the standard equations of circles. Students examine guided notes, review guided practice, watch...

The equation of a circle is the focus of this site. Topics include tangents, intersecting circles, and intersection of lines and circles. Examples and a practice test are available.

In this activity, students investigate the relationship between the coordinates of a point on the circle, radius of a circle, and the values in the equation of the circle.

This site, which is provided for by the University of St. Andrews, allows you to zoom in/out and add evolutes, involutes, etc.

A comprehensive guide for learning all about equations with definitions, how to solve them, solved examples, and practice questions.

Explore the relationship between the center and radius of a circle and the equation of the circle. Collect data and determine regression equations related to various combinations of data, and use the regression equations to make...

The online assessment exhibits knowledge of advanced mathematical concepts in Trigonometry. The questions evaluate students on the topic of circles.

This site offers a problem and solution to finding all possible slopes for a line tangent to a circle given a particular equation of a circle. Could be an interesting challenge for students.

Provides a long list of physics formulas for easy reference.

Use the fact that the arc measures of a circle must sum to 360 degrees to find missing arc measures by setting up equations. Students receive immediate feedback and have the opportunity to try questions repeatedly, watch a video or...

Various forms of equations of circles are presented at the Math Forum: center-radius form, general form, diameter form, three-point form, and parametric form.

[Free Registration/Login may be required to access all resource tools.] This lesson covers changing a general second-degree equation into the standard form of a parabola, ellipse, circle or hyperbola. Students examine guided notes,...

Use this tutorial to learn about the standard-form equation for a circle. Several step-by-step solutions and examples help you understand the part of the circle and how they relate to the equation.

Dr. Math, in reply to a student question, shows how a specific pair of parametric equations produces a circle as opposed to an ellipse.

Students will learn about the equation for a circle by using a Study Cards stack. Later, students will attempt to match the graph of a circle from a digital picture, using the form learned previously, and approximating the center and...

This downloadable java simulation models the 2D energy eigenstates of a particle trapped in a very deep two-dimensional circular well.