Worlds of David Darling
Encyclopedia of Science
   
Home > Encyclopedia of Science

annulus




annulus
The region between the smaller and the larger of two circles that share a common center. The area of an annulus is the difference in the areas of the larger circle of radius R and the smaller one of radius r:
A = πR 2 - πr 2 = πR 2 - πr 2.

Related category

   • GEOMETRY