# Triangle calculator SSS - result

Please enter the triangle sides:

### Obtuse scalene triangle.

Sides: a = 12.9   b = 6.5   c = 6.68

Area: T = 8.71440539727
Perimeter: p = 26.08
Semiperimeter: s = 13.04

Angle ∠ A = α = 156.3355251319° = 156°20'7″ = 2.72985648724 rad
Angle ∠ B = β = 11.66884422702° = 11°40'6″ = 0.20436527362 rad
Angle ∠ C = γ = 11.99663064109° = 11°59'47″ = 0.20993750449 rad

Height: ha = 1.35110161198
Height: hb = 2.68112473762
Height: hc = 2.60989981954

Median: ma = 1.35441417946
Median: mb = 9.74444189155
Median: mc = 9.65326887446

Inradius: r = 0.66882556728
Circumradius: R = 16.06993863543

Vertex coordinates: A[6.68; 0] B[0; 0] C[12.63334131737; 2.60989981954]
Centroid: CG[6.43878043912; 0.87696660651]
Coordinates of the circumscribed circle: U[3.34; 15.71884470544]
Coordinates of the inscribed circle: I[6.54; 0.66882556728]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 23.66547486812° = 23°39'53″ = 2.72985648724 rad
∠ B' = β' = 168.332155773° = 168°19'54″ = 0.20436527362 rad
∠ C' = γ' = 168.0043693589° = 168°13″ = 0.20993750449 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    