About the Inradius Area
The inradius is the radius of the circle tangent to all three sides of a triangle.
The semiperimeter is half the triangle perimeter.
This relationship is especially useful in advanced geometry and competitive mathematics.
Calculate triangle area from its inradius and semiperimeter using the standard area relationship A = r × s.
Fill in the details and click Calculate to see your results.
The inradius is the radius of the circle tangent to all three sides of a triangle.
The semiperimeter is half the triangle perimeter.
This relationship is especially useful in advanced geometry and competitive mathematics.
| Inradius r | 4 cm |
| Semiperimeter s | 15 cm |
| Triangle Area | 60 |
| Valid Input | 1 |
The triangle area is 60 square centimetres.
Try this example →Area equals the inradius multiplied by the semiperimeter.
It is half the perimeter, or (a+b+c)/2.
It is the radius of the incircle, the circle tangent to all three sides.
No. Convert them to the same length unit before calculating.