# Triangle calculator SSS - result

Please enter the triangle sides:

### Obtuse scalene triangle.

Sides: a = 12.9   b = 6.5   c = 18.6

Area: T = 24.07328062344
Perimeter: p = 38
Semiperimeter: s = 19

Angle ∠ A = α = 23.46773699372° = 23°28'3″ = 0.41095828722 rad
Angle ∠ B = β = 11.57553743732° = 11°34'31″ = 0.2022028395 rad
Angle ∠ C = γ = 144.957725569° = 144°57'26″ = 2.53299813864 rad

Height: ha = 3.73222180208
Height: hb = 7.40770173029
Height: hc = 2.58884737886

Median: ma = 12.34991902569
Median: mb = 15.67223482606
Median: mc = 4.22437424164

Inradius: r = 1.26769898018
Circumradius: R = 16.19768029902

Vertex coordinates: A[18.6; 0] B[0; 0] C[12.63876344086; 2.58884737886]
Centroid: CG[10.41325448029; 0.86328245962]
Coordinates of the circumscribed circle: U[9.3; -13.26107099019]
Coordinates of the inscribed circle: I[12.5; 1.26769898018]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 156.5332630063° = 156°31'57″ = 0.41095828722 rad
∠ B' = β' = 168.4254625627° = 168°25'29″ = 0.2022028395 rad
∠ C' = γ' = 35.04327443104° = 35°2'34″ = 2.53299813864 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    