Difference between revisions of "Inradius"

Revision as of 00:24, 11 March 2008

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

If $\triangle ABC$ has inradius $r$ and circumradius $R$ , then $\cos{A}+\cos{B}+\cos{C}=\frac{r+R}{R}$ .

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-The '''inradius''' of a [[polygon]] is the [[radius]] of its [[incircle]] (assuming an incircle exists).
+The '''inradius''' of a [[polygon]] is the [[radius]] of its [[incircle]] (assuming an incircle exists). It is commonly denoted <math>r</math>.
+== 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>.
 [[Category:Geometry]]