Inscribed Circle Radius Calculator (r = A/s)
This calculator computes the inscribed circle radius: exact formula r = A/s, worked example 3-4-5 cm triangle → A = 6, s = 6 → r = 1 cm.
- Free, instant, any units.
Figures are estimates from this calculator’s standard formula — adjust the inputs in the tool below for your exact number.
How the inscribed circle radius Calculator Works
The calculator applies the exact formula r = A/s (inradius). Worked example: 3-4-5 cm triangle → A = 6, s = 6 → r = 1 cm. Keep every input in one unit system and the result follows in length units (m, ft, cm); full precision is kept until the final rounding. Angles in radians pair with s = rθ; convert degrees with × π/180.
- 1
Enter the measurements
Type the values required by the formula for inscribed circle radius.
- 2
Check the units
One unit system throughout — cm, m, ft or in.
- 3
Read the result
The calculator substitutes, evaluates and rounds only at the end.
Use Cases
Fabrication and layout work
Wire, trim and route length planning
Design and homework verification
Tips
- 1
Keep angles in radians for s = rθ formulas
- 2
1 rad = 57.2958°; degrees × π/180 = radians
- 3
Unroll curved paths into straight segments to sanity-check
Common Mistakes
Degrees entered where radians are required
Using the chord length as the arc length
Rounding π too early in chain calculations
FAQs
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