Learn about the radius of a circle with this useful reference guide. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.

A basic review of circles and how to calculate the circumference, radius, diameter, and area. Includes practice questions.

This task provides a good opportunity to use isosceles triangles and their properties to show an interesting and important result about triangles inscribed in a circle with one side of the triangle a diameter. The fact that these...

This site contains an extensive list of various units of measurement known internationally and across several disciplines. Unit symbols are also included.