Area of an annulus

Abstract:

A web page and interactive applet show how to compute the area of an annulus. Text on the page explains that the area is the overall area minus the area of the circular 'hole' in the center. For those who prefer it in a formula that is given. The user can resize the two circles defining the annulus and visually estimate the area from a unit grid drawn inside it. A companion page is Definition of an Annulus at http://www.mathopenref.com/annulus.html Applet can be enlarged to full screen size for use with a classroom projector. This resource is a component of the Math Open Reference Interactive Geometry textbook project at http://www.mathopenref.com.

Subject:

Mathematics and Statistics

Grade Level:

Secondary

Collection:

Math Open Reference