How does the Inscribed Circle Radius work?

Inradius r = Area / s where s = semi-perimeter Then: Area computed by Heron's formula Then: The incircle touches each side exactly once Then: Larger triangles with shorter perimeters have larger inradii.

Can you give an example of how to use the Inscribed Circle Radius?

Example: Input 3, 4, 5 right triangle gives a result of Inradius = 1.

Is the Inscribed Circle Radius free to use?

Yes — completely free with no registration, download, or subscription required. All calculations happen instantly in your browser.

How accurate is the Inscribed Circle Radius?

Our Inscribed Circle Radius uses verified mathematical formulas and is accurate to multiple decimal places. Results are calculated in real-time using the same methods used by professionals.

Matematika

Inscribed Circle Radius

Inscribed Circle (Inradius)

Side a

Side b

Side c

The incircle calculator finds the inscribed circle radius for a triangle with given side lengths.

Symbol	Name	Unit	Description
a, b, c	triangle side lengths	length	—
r	inradius	length	—
s	semi-perimeter	length	—

Triangle Type	Sides	Inradius
Right	3,4,5	1.00
Right	5,12,13	2.00
Equilateral	6,6,6	1.73
Isosceles	5,5,6	1.50

References

›Incircle — Wolfram MathWorld

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Inscribed Circle Radius

Inscribed Circle (Inradius)

Ano ang Inscribed Circle Radius?

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