A wealth of resources to supplement instruction on parts of the circle. Find lessons describing chords, tangents, secants, and segments, as well as related practice quizzes and classroom activities.

Understand the concept of circumference by learning the definition, circumference geometry definition, circumference equation, and circumference of a circle formula. Check-out the interactive simulation for better understanding and try...

[Free Registration/Login may be required to access all resource tools.] This study guide reviews the terminology for circles (tangent, arcs, central angles) and the equation for a circle.

Given the center and radius of a circle, determine if a point is inside of the circle, on the circle, or outside of the circle.

Here is a project that combines Computer Science and Mathematics. Prove a method for inscribing a circle within a triangle (as shown). You'll also learn how to create an interactive diagram to illustrate your proof, using an applet that...

Here is a project that combines Computer Science and Mathematics. Prove a method for circumscribing a circle about a triangle (as shown). You'll also learn how to create an interactive diagram to illustrate your proof, using an applet...

Here is a project that combines Computer Science and Mathematics. The two circles are tangent to one another at point A. Their diameters are parallel. Prove that points A, D and F are co-linear. You'll also learn how to create an...

Learn how an inscribed circle is the largest circle contained within the triangle.

When a line intersects a circle in exactly one point the line is said to be tangent to the circle or a tangent of the circle.

Learn how the components and properties of a sphere are analogous to those of a circle.

Recall that a portion of a circle is called an arc. One way to measure an arc is with degrees.

This a straightforward, but interesting, project in geometry. It is a good first proof to try on your own. You should be able to figure it out by yourself, and you'll gain insight into a basic property of circles.

The interactive tutorial examines the properties of central and inscribed angles intercepting a common arc in a circle. Learners use the applet to find central and inscribed angles.

Here is a project that combines Computer Science and Mathematics. The semicircle has two tangent lines that meet at point T. You need to prove that a line drawn from A to T bisects CD. You'll also learn how to create an interactive...

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.

This online calculator will calculate the various properties of a right circular cone given any 2 known variables.

This site, which is provided for by the University of St. Andrews, contains information on the mathematician Gregory and his accomplishments.

This lesson allows students 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 created as a result...

Learn about the tangent definition in geometry, tangent geometry, tangent to a circle, tangent line equation. Check-out the solved examples for better understanding and try your hand at the tangent line calculator or solving a few...

Mini-lesson takes a look at the definition and shape of a cylinder, cylinder formula, cylinder volume, and cylinder surface area. Try your hand at the cylinder surface area calculator and interactive questions for better understanding.

Solve two problems that apply properties of tangents to determine if a line is tangent to a circle.

Solve two problems that apply properties of tangents to determine if a line is tangent to a circle.

[Free Registration/Login Required] Answer questions about the halves and fourths of circles and rectangles, and collect coins for each correct answer.

This University of St. Andrews site contains biographical information and findings of Christiaan Huygens.