Triangle Incircle Calculator

Find the inscribed circle radius, incenter coordinates, area, and semiperimeter of a triangle from its three sides a, b, c.

Input

Enter the three side lengths a, b, and c of a triangle to compute the inscribed circle radius, incenter coordinates, area, and semiperimeter.

Side a

Side b

Side c

Inradius r

Area

Semiperimeter s

Incenter

(2, 1)

Length units follow your input. Area is in squared units, and coordinates assume side a lies along the x axis.

The semiperimeter s is half the sum of the sides, s = (a + b + c) / 2.
The area is found with Heron formula, area = sqrt(s (s - a)(s - b)(s - c)).
The inradius r is the area divided by the semiperimeter, r = area / s.
The incenter is the weighted average of the three vertices using the opposite side lengths as weights, and it is the center of the circle tangent to all three sides.
For three sides to form a triangle, each must be positive and the sum of any two sides must exceed the remaining side.

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