# Triangle calculator SSS - result

Please enter the triangle sides:

### Obtuse scalene triangle.

Sides: a = 6   b = 15   c = 18

Area: T = 42.15437364892
Perimeter: p = 39
Semiperimeter: s = 19.5

Angle ∠ A = α = 18.19548723388° = 18°11'42″ = 0.31875604293 rad
Angle ∠ B = β = 51.31878125465° = 51°19'4″ = 0.89656647939 rad
Angle ∠ C = γ = 110.4877315115° = 110°29'14″ = 1.92883674304 rad

Height: ha = 14.05112454964
Height: hb = 5.62204981986
Height: hc = 4.68437484988

Median: ma = 16.29441707368
Median: mb = 11.12442977306
Median: mc = 7.03656236397

Inradius: r = 2.16217300764
Circumradius: R = 9.60876892283

Vertex coordinates: A[18; 0] B[0; 0] C[3.75; 4.68437484988]
Centroid: CG[7.25; 1.56112494996]
Coordinates of the circumscribed circle: U[9; -3.36326912299]
Coordinates of the inscribed circle: I[4.5; 2.16217300764]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 161.8055127661° = 161°48'18″ = 0.31875604293 rad
∠ B' = β' = 128.6822187453° = 128°40'56″ = 0.89656647939 rad
∠ C' = γ' = 69.51326848853° = 69°30'46″ = 1.92883674304 rad

# How did we calculate this triangle?

### 1. The triangle circumference is the sum of the lengths of its three sides ### 2. Semiperimeter of the triangle ### 3. The triangle area using Heron's formula ### 4. Calculate the heights of the triangle from its area. ### 5. Calculation of the inner angles of the triangle using a Law of Cosines    