Annulus of a Circle

on . Posted in Plane Geometry

annulusThe area between two concentric circles.

Annulus of a Circle Index

 

Area of an Annulus formulas

\( A \;=\; \pi \;r^2 - \pi \; R^2 \)

\( A \;=\; \pi \; ( r^2 - R^2 ) \)

Symbol English Metric
\( A \) = area \( in^2 \) \( mm^2 \)
\( r \) = inside radius \( in \) \( mm \)
\( R \) = outside radius \( in \) \( mm \)
\( \pi \) = Pi \(3.141 592 653 ...\)

  

Inside Radius of an Annulus formula

\( r \;=\; \sqrt{  R^2 - ( A \;/\; \pi )   }  \)
Symbol English Metric
\( r \) = inside radius \( in \) \( mm \)
\( A \) = area \( in^2 \) \( mm^2 \)
\( R \) = outside radius \( in \) \( mm \)
\( \pi \) = Pi \(3.141 592 653 ...\)

  

Outside Radius of an Annulus formula

\( R \;=\; \sqrt{  r^2 - ( A \;/\; \pi ) }  \)
Symbol English Metric
\( R \) = outside radius \( in \) \( mm \)
\( A \) = area \( in^2 \) \( mm^2 \)
\( r \) = inside radius \( in \) \( mm \)
\( \pi \) = Pi \(3.141 592 653 ...\)

  

Area of a sector of an Annulus formula

\( A \;=\; ( \pi \; \theta\;/\; 360^{\circ} ) \; ( R^2 - r^2 ) \)
Symbol English Metric
\( A \) = area \( in^2 \) \( mm^2 \)
\( \theta \) = degree \( deg \) \( rad \)
\( r \) = inside radius \( in \) \( mm \)
\( R \) = outside radius \( in \) \( mm \)
\( \pi \) = Pi \(3.141 592 653 ...\)

  

Breadth of an Annulus formula

\( b \;=\; R - r \)
Symbol English Metric
\( b \) = breadth \( in \) \( mm \)
\( r \) = inside radius \( in \) \( mm \)
\( R \) = outside radius \( in \) \( mm \)

  

Longest Interval of an Annulus formula

\( l \;=\; 2 \; \sqrt{ R^2 - r^2 } \)
Symbol English Metric
\( l \) = longest interval \( in \) \( mm \)
\( r \) = inside radius \( in \) \( mm \)
\( R \) = outside radius \( in \) \( mm \)

 

Perimeter of an Annulus formula

\( P \;=\; 2 \; \pi \; ( R + r ) \)
Symbol English Metric
\( P \) = perimeter \( in \) \( mm \)
\( r \) = inside radius \( in \) \( mm \)
\( R \) = outside radius \( in \) \( mm \)
\( \pi \) = Pi \(3.141 592 653 ...\)

 

Piping Designer Logo 1

Tags: Circle