Difference between revisions of "Inradius"

(Properties)
(Properties)
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== Properties ==
 
== Properties ==
 
*If <math>\triangle ABC</math> has inradius <math>r</math> and [[circumradius]] <math>R</math>, then <math>\cos{A}+\cos{B}+\cos{C}=\frac{r+R}{R}</math>.
 
*If <math>\triangle ABC</math> has inradius <math>r</math> and [[circumradius]] <math>R</math>, then <math>\cos{A}+\cos{B}+\cos{C}=\frac{r+R}{R}</math>.
*If <math>\triangle ABC</math> has inradius <math>r</math> and [[semi-perimeter]] <math>s</math>, then the [[area]] of <math>ABC</math> is <math>rs</math>.
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*If <math>\triangle ABC</math> has inradius <math>r</math> and [[semi-perimeter]] <math>s</math>, then the [[area]] of <math>\triangle ABC</math> is <math>rs</math>.
 
[[Category:Geometry]]
 
[[Category:Geometry]]

Revision as of 13:54, 14 March 2010

The inradius of a polygon is the radius of its incircle (assuming an incircle exists). It is commonly denoted $r$.

Properties