# Triangle calculator SSS - result

Please enter the triangle sides:

### Obtuse scalene triangle.

Sides: a = 12   b = 21   c = 28

Area: T = 115.762241834
Perimeter: p = 61
Semiperimeter: s = 30.5

Angle ∠ A = α = 23.18880202295° = 23°11'17″ = 0.40547073 rad
Angle ∠ B = β = 43.55659049333° = 43°33'21″ = 0.76601939498 rad
Angle ∠ C = γ = 113.2566074837° = 113°15'22″ = 1.97766914038 rad

Height: ha = 19.29437363901
Height: hb = 11.02549922229
Height: hc = 8.26987441672

Median: ma = 24.01104144071
Median: mb = 18.80882428738
Median: mc = 9.82334413522

Inradius: r = 3.79554891259
Circumradius: R = 15.23881059872

Vertex coordinates: A[28; 0] B[0; 0] C[8.69664285714; 8.26987441672]
Centroid: CG[12.23221428571; 2.75662480557]
Coordinates of the circumscribed circle: U[14; -6.01766331179]
Coordinates of the inscribed circle: I[9.5; 3.79554891259]

Exterior(or external, outer) angles of the triangle:
∠ A' = α' = 156.8121979771° = 156°48'43″ = 0.40547073 rad
∠ B' = β' = 136.4444095067° = 136°26'39″ = 0.76601939498 rad
∠ C' = γ' = 66.74439251627° = 66°44'38″ = 1.97766914038 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    